does snow graves prevent the guys coming into play via things in the ground?

No.

Things in the Ground is a replacement effect. The characters never actually make it to the discard pile. Thus Snow Graves cannot freeze them there.

ok i figured as much but i was hoping against hope

Magnus Arcanis said:

How about 'Eat the dead'? Here's the card text:

Attach to a character you control.
Response: When attached character is destroyed, attach it and Eat the Dead to any domain you control as resources.

I suppose it and the character it was attached to never enter the discard pile, or do they? I'm a bit uncertain since it doesn't use the word 'instead'.

Edit: I think it's already been asked, but 'Chant of Thoth' _is_ blocked by Snow Graves, right?

Action: Choose up to 3 Spell or Artifact cards in your discard pile. Until the end of the phase, you may play those cards as though you were playing them from your hand. If any of the chosen cards are event cards, put them on the bottom of your deck instead of discard pile after playing them.

In order to play the cards, they'd have to leave the discard pile, so it doesn't work. I seem to remember it was clarified when asking about Yog-Sothoth Lord of Time and Space:

Action: Pay 2 to choose and play a Spell event card from your discard pile without paying its costs. Then, place that card on the bottom of your deck.

jhaelen said:

For Eat the Dead. Snow Graves would stop the ability. As Eat the Dead wouldn't trigger until after it (and the character) is in the discard pile.

Also, Chant of Thoth is indeed blocked by Snow Graves.

from faq 1.5 under playing events.

"When a player plays an event from his
discard pile, it does not remain in his
discard pile, but rather is placed back
in his discard pile after the action is
complete."

We alreay know your character and support cards can't come out, but this rule means that your event cards can't come out either. An event still needs to go to that... wierd "limbo" area first and be placed on top of your discard pile (after its done doing its thang). Which it can't do if Snow Graves is freezing things up.

Magnus Arcanis said:

I thought, 'Eat the Dead' might be a replacement effect, but apparently that requires a wording using 'instead' at some point.

jhaelen said:

Technically I think we could also get away with it being a replacement effect if the effect was a Disrupt as it would trigger before the cards entered the discard pile. My main reasoning for Eat the Dead was because it was a response. A R esponse like this has to trigger from the discard pile which is why snow graves would catch it.

Though, using the word instead on replacement effects is just a good idea to make things clear for everyone.

PS. Do you guys see the bolding and capitilzation of keywords like above a good thing for the rules discussion forum? I tried to start doing it so lurkers and new players could more easily pick up what we were talking about, but it could also seem like I'm doing it to make a drastic point. Could use some feedback on this one. Trying to keep drastic points to underline or quotes to help this but not sure if its coming off right.

Magnus Arcanis said:

I like it too. It highlights that a word is being used in the sense of specific game terminology rather than in the general English sense.