Ideas:
-snip-
Diamond stuff: I'm working on it. Currently, I'm making a Diamond Crafting workshop that uses gem cutting as a skill - hopefully you should be able to create diamond everything after the diamonds have been processed there (diamond is candy's evil twin, they're coloured the same although diamond should probably form less edge and have realistic density). Now, I think the only way to do this is to add "Diamond" to the metals list for use in the forge, but that's somewhat fitting - since the smelter seems to run off reactions, making a separate workshop for a separate reaction (diamonds -> majickle craft-diamonds) is all that's needed. For now.
Planks/blocks: That recent sawmill mod sounds like a great way to integrate this, especially since in Minecraft (for you not in the know 
) you can turn one log into four buildable planks. I'll talk to that guy about it.
Neat, my ideas are being used! Will the diamond stuff be in in time for Caverncrept?
Gunpowder itemcorpse: I considered this one. But I don't know if you can have more than one itemcorpse, since creepers already drop creepite (flashboiling rock, also used for ghast fireballs). The ghast fireballs was just me wanting to recycle my explodey material, it could be changed, but I don't know about multiple drops (or if the gunpowder would just get destroyed).
I mentioned a way to do this; if you're interested, I could go over it in more detail.
Gather snowballs: I don't know how, but this could be fun. Maybe make "snowballs" a tundra-only plant that only grows in winter. Then you could either use them as hilariously weak crossbow ammo or craft them into the also hilarious Snow Ballista Bolts. That sounds tricky and annoying, so I'll have to look for better solutions.
I was imagining that snow balls would be an ammo you could produce for free in a special workshop or something, which because of how low the melting temperature is for snow would have to be outdoors in a freezing area.
Books: Well, we have our custom-reaction blank game-object books. So I have an idea not involving those!
- "Writer's Office" workshop, requires some crafty labour
- Convert large amounts of paper into books, along with some leather for binding
- Books can be converted into bookshelf furniture (can you add new furniture?) at the same workshop.
- Or they can be used as a valuable trade good!
Alternatively, all the workshop does is make the blank books that necromancers already write.
re:Furniture: I think I mentioned this. Technically, no, but you CAN add new tools, have custom workshops require those tools, and use the workshops to raise the value of a room. As to the rest: Pretty good.
Sugar cane: Definitely, they should be convertible into sugar and syrup as well, and be used for paper (perhaps at yet another custom workshop, the Pulp Mill, which can also use wood)
Again, it might make sense to have rope reed be paper-able as well.
Reclaiming stuff: Oooh, blocks. I like the idea of turning Minecrafty materials into buildable blocks, valuable blocks that you could use to raise the value of stuff that requires blocks (screw pumps, wells?).
Most "minecrafty" stuff can already be turned into blocks--wood, stone, metal...well, that's about everything except gems. Minecraft blocks can usually also be turned back into raw materials.
Bone meal: Yes please! That should be fairly easy using pre-existing bones. It would be done at the Soap Maker's workshop because I'm sick of thinking up all these custom workshops
Heh, good point.
Only one corpse item.
Except by the workaround where the creepite explosion is an attack which has a syndrome that turns the creeper into a creature that will die quickly and leave no corpse--say, an "exploded creeper" which has all of its bodily materials evaporate at a temperature one degree below HOMEOTHERM, and then the gunpowder is the normal itemcorpse. Sadly, it takes away explosions-on-death...
Bone meal, it must be noted, is already considered in vanilla DF, just not manufacturable.
Know how to make a custom reaction manufacture it?
