Things I know:

The reanimate can attack once per turn.

The reanimate cannot open doors.

The reanimate cannot perform special actions.

The reanimate cannot stand up heroes.

etc

Basically, the reanimate can only attack once per turn and/or move once or twice (if it didn't perform an attack).

What other cases apply to the reanimate, as it counts as a figure (and a hero, or not?)

Like in Sindaeas Secret, the master crow hag can only be damaged by hero attacks - does the reanimate count?

Any other cases we can/should be aware of in our campaign?

A familiar has one move action and some familiars also get one attack action. This is different to getting two actions because those familiars can not use their one move action to perform an attack or vice versa. However, they are allowed to spend one of their actions to remove the stunned condition since it does not require a special action to remove it. This means that familiars can not remove conditions like bleeding or burning.

Familiars treated like figures can be affected by:

1) Monster attacks and abilities

2) OL cards

3) Hero abilities and skills

In the above cases you can read 'reanimate' when it says 'hero', in other cases the rules refer to actual heroes with hero sheets. Like plot cards and quest rules.

Hopes this helps!

Thank you!

Do you have any more hands on examples?

Or a straight up and down sentence I can use to describe the limitations of familiars to the hero players in our group?

The end of Page 17 and the start of Page 18 in the rulebook actually does a pretty good job of detailing how familiars work, and how familiars that are treated as figures work.

When it comes to familiars treated as figures, what to keep in mind is that they always counts as figures, and they never actually counts as heroes other than as explicitly detailed on pg. 18. That is that they "... may be
targeted and affected by monster attacks, hero abilities, and Overlord cards that target a hero."

So if it says hero in quest text, it never applies to the familiars, for example. They are not heroes - they can merely be targeted by certain things that usually only targets heroes. They are also subject to terrain effects as if they were heroes - but this (to the best of my knowledge) also applies to all other figures - which familiars are not, unless they explicitly count as figures - in the game (unless explicitly stated otherwise), so it should go without saying.

So in the specific case mentioned in your OP, no, the reanimate doesn't count as a hero. It is a common mistake (and one I did myself) to think of "familiars treated as heroes" as "pretty much heroes, right?", but just drop that idea. They never ever "count as" heroes. It is just that certain things that normally only affect heroes can also affect them.

In essence, familiars that count as figures can only perform actions that explicitly allowed them (usually by an ability card of the controlling hero, or on the familiar card itself) or actions that specify that they can be performed by any figure or familiar (the latter which has never happened, to the best of my knowledge). They cannot open doors, they cannot take rest actions, they cannot revive fallen heroes, etc.

If you ever find yourself wondering "Can the familiar do this?" , if it's not explicitly stated on the familiars cards, in the small section on pg. 17-18, in the ability cards of the controlling hero, or (in the case of familiars that count as figures) as a general rule (such as for a quest) regarding "figures", the familiar absolutely can't do it . This leads to some funny situations (one that cropped up on the boards the other day involved Skye, a hawk familiar that does not count as a figure, not being able to "jump" from a window), but dems the rules.

Edit: Also, like Caesarsalad said, note that familiars (again, unless otherwise specified) can take one move action and one attack action. In your OP, you mention that they can only attack once per turn, but just to be clear, they also can only move once per turn. You cannot choose to not take an attack, and instead move twice, as most monsters can. You still get two actions, but a maximum of one movement action, and a maximum of one attack action - again, unless specified otherwise. You probably know this and just didn't list that limitation, but just in case, I wanted to mention it.

I think the more confusing situation is when the quest text states that "Heroes may attack X as if it were a Monster". Where X is usually some objective token. (I don't have the wording infront of me, so it may be "X may be attacked by a hero as if it were a monster")

In one hand, it is quest text so it does not apply to familiars.

On the other hand, the text is outlining the rules for the objective token, and explicitly states it is treated as a monster, which familiars treated as heroes can attack..

(Example of this would be the 2nd encounter of the Shadow of Nerekhall quest with Verminous (sorry don't have the book with me), where the rift may be attacked).

I most definitely did not! I dont know how I missed that from the rules...

I think the more confusing situation is when the quest text states that "Heroes may attack X as if it were a Monster". Where X is usually some objective token. (I don't have the wording infront of me, so it may be "X may be attacked by a hero as if it were a monster")

In one hand, it is quest text so it does not apply to familiars.

On the other hand, the text is outlining the rules for the objective token, and explicitly states it is treated as a monster, which familiars treated as heroes can attack..

(Example of this would be the 2nd encounter of the Shadow of Nerekhall quest with Verminous (sorry don't have the book with me), where the rift may be attacked).

With a strict reading of that, only heroes would be allowed to attack the concerned target. Even if it's "as if it were a monster", the qualifier is still "Heroes". As in, only heroes can attack the target, as if it was a monster. It doesn't imply that the target is a monster at all, merely that heroes may attack it as if it is a monster. This would completely exclude familiars.

However, that being said, a less strict reading would imply that "the heroes" are the hero players as a whole, not specifically "a hero". Generally, this is what I'd read it as intending, depending on the situation, I think, and I'd generally consider it an oversight. But if it'd ever cause a legitimate issue, I'd default to RAW, but my players have generally been amicable when things like "This makes no fudging sense" comes up.

Edit: You probably know this and just didn't list that limitation, but just in case, I wanted to mention it.

I most definitely did not! I dont know how I missed that from the rules...

It's easy to miss, but it's in this part on pg. 17:

"When activated, a familiar may perform a move action following the same rules as heroes. Familiars treat any special terrain (other than obstacles) as water during their movement. The familiar may perform additional types of actions during its activation, as noted on its Familiar card. These additional actions, unless otherwise noted, may be performed in addition to the move action and may interrupt the move action in a way similar to hero move actions. If no such other actions are noted, then all the familiar can do on its turn is move up to its Speed value."

And most familiars that are treated as figures are noted as being able of performing one attack action. But strictly speaking, familiars, unless otherwise noted, can pretty much just move up to their speed once per turn and that's it.

Luckmann and others have done a very good job explaining things in this topic. If you want additional examples/ descriptions, check out my glossary (see the link in my signature).