Background:
Like RtL, the new props in SoB are not actually defined. It is important to fully define props due to interactions with cards or abilities that affect obstacles (like Fly, Acrobat), large monster movement and similar. The rules have exisiting classifications as 'Obstacles', 'Traps' and 'other props' (as well as 'Treasure'), which generally work well.
It is also important to get a definition for 'terrain' - this term is used several times but has no definition at all!
Does 'Terrain' include all props? (Tables?)
Just obstacles? (Fog? Scything Blades, which are not obstacles but are explicitly referred to as damaging terrain examples in the FAQ?)
Just props which do not (normally) move? (Rolling Boulders?)
Only naturally occurring props (Throne?)
Ship stuff (cannon mounts? masts?)
Only stuff printed on the map pieces (trees, mud, water, but not the same props as tokens laid over the map?)
Just about any easy definition I can think of has a problem or uncertainty somewhere. But it is probably better to have a definition with some minor problems, than not have a definition at all!
The following new props from SoB are undefined:
Anchor, Barrel, Cage, Captains Wheel, Cavern Entrance, Forecastle, Hold, Mast, Pipe Organ, Railing, Reef, Rope, Sandbar, Scrub, Statue, Water (Deep), Water (Shallow), Weapon Mount (empty), Weapon Mount (with Cannon), Whirlpool
My Guess is that Anchor, Rope and Captains Wheel might not be obstacles since they have no discernible effects of obstacle type (they do not affect movement or have affects upon figures occupying them in any way at all).
Forecastle is likely just a prop since it too has no discernible effects of obstacle type, even though it counts as elevated terrain (a subtle difference).
Railing is unlikely to be an obstacle because it is not a space type - it fits between the spaces like a wall really.
Scrub might not be an obstacle because again, it has no effect on figures entering it or occupying it - its affect is on the attacks of figures not in the scrub itself (this is different from the shadowcloak given by trees, for example, because the trees give the shadowcloak to the figure in them rather than affecting the attacks of another figure directly).
The Cavern Entrance is probably not an obstacle because it is analogous to a portal space - similarly the Hold. The skull spaces may or may not be obstacles (probably not) - in at least one island level they are impassable, though usually they have no effect.
Everything else (Barrel, Cage, Mast, Pipe Organ, Reef, Sandbar, Water (both), Weapon mount (both) and Whirlpool) seem likely to be obstacles.
The main reason for this coming up is the ability to ignore the effects of obstacles - fly, mostly (there is no acrobat), but also large monsters!
Thematically, probably only the cage is dubious as being 'ignorable' for flyers. Since it blocks movement*, I don't think it is an issue with large monsters.
As an interesting aside, since a cage blocks movement can a (small) figure move around inside the cage? Perhaps the cage actually needs
new rules entirely and 'blocks movement' is insufficient. Perhaps...
"Figures may not enter or exit the cage prop unless they fulfill scenario rules. Figure inside a cage may move around inside the cage freely. The cage is not an obstacle." ... which would solve all potential cage movement issues 'thematically', and reasonably, I think.
Questions and Answers:
Q1: What new props in SoB qualify as obstacles?
A1: X, Y and Z are obstacles. A, B and C are not obstacles.
Maybe add explanations for some that are not obstacles?
Q2: Can small figures move inside a cage since it blocks movement?
A1: No. Since the cage blocks movement figures in a cage may not move at all.
A2: Yes, small figures may move inside the cage, but may not enter or exit the cage.
A3: "Figures may not enter or exit the cage prop unless they fulfill scenario rules. Figure inside a cage may move around inside the cage freely. The cage is not an obstacle."
Please note that answer 3 is much preferable to answer 2 because it completely defines the cage and solves several issues while being fundamentally the same - unless the cage is an obstacle which fly-ers (and Soar-ers) can ignore.
Q3: What does the term 'terrain' include?
A1: 'Terrain' includes all obstacles, traps and other props.
A2: 'Terrain' includes all obstacles and other props. It does not include traps.
Either change FAQs large monster reference or explain.
A3: 'Terrain' includes all obstacles, traps and other props except; .....
(list exceptions)