If you go the dragonhide route, just stick with a dragonhide breastplate. You are already proficient in it, and IIRC, Wild only adds the enhancement bonus to your AC in Wildshape anyway.
Wild adds the base armor bonus of the armor and the enhancement bonus to AC, both.
I was looking for ways to beef up his AC.
. . .
Would it be better to go Monk's Belt and focus on Wisdom buffs or Wild Dragonhide Plate and look for some way to pick up Heavy Armor Proficiency? The monk's belt is attractive since we do fight casters often. Also, for the animal companion, should I buy him heavy armor as well?
In the short run, +1 wild dragonhide full plate gives +9 AC and a +1 wild dragonhide breastplaste gives +6 AC. In the long run, +5 wild dragonhide full plate gives +13 AC, or a +5 wild dragonhide breastplaste gives +10 AC. A monk's belt gives +6 AC (assuming your DM allows it to give +Wis to AC) right now and eventually either +12 AC or +13 AC, assuming you started with 18 Wis and added +1 to it at 4th and 8th levels. The wild dragonhide full plate has slightly more AC right for the cash invested right now and will up until you can get a +5 tome, but the monk's belt is more efficient in the long run because you have to sink all that cash into your Wis anyways. If you have to do anything to get proficiency with heavy armor, that makes the full plate much less appealing: note that some people argue that because wild armor "cannot be seen" while wild shaped, its ACP and thus the non-proficiency penalty don't apply in wild shape. Personally, I would
never allow that, but I also wouldn't allow a
monk's belt to give a non-monk Wis to AC because I see no reason to ever come down on an ambiguous rules question in a way that makes the core full casters more outrageously powerful than they already are. Your DM may disagree.
If you only get the one wilding clasp, you might want to run with the breastplate anyways so you can put it on your +Str item. I don't know of any way in the core to avoid spending a feat for heavy armor proficiency or losing a caster level to take a class with heavy armor proficiency.
There are other ways to increase your AC. With Extend Spell, you can use four 3rd-level slots to put barkskin up 8 hours a day, which is close to or at all-day duration. This is probably not economical yet, but in another three levels or so it will be for another +4 or +5 to AC. Depending on how your DM interprets how animated interacts with wild shape, you should also look into an animated heavy darkwood shield. (Because wild shape says only "worn and carried equipment" melds and you don't carry an animated shield, I think it's clear that animated shields don't meld, but again, your DM may disagree.) That will give you +3 AC for about 10k and more with more money invested. Similar rules logic applies to the dusty rose (+1 AC) and deep red (+2 Dex so +1 AC) ioun stones. You can also wildling clasp a ring of deflection, eventually. If your DM won't let you buy these items, consider taking Craft Wondrous to make them.
Technically, animals are, "Proficient with no armor unless trained for war." It's not clear what being "trained for war" means other than that warhorses and riding dogs are, since there's no Handle Animal trick that specifically covers "trained for war" or armor proficiency. Ask your DM. If your mount isn't proficient and can't be trained, you have to stick to minimal-ACP light armor. Even with proficiency, barding for Large animal companions is four times as expensive as normal armor and not cheap even if you don't bother with any magical enhancements. I prefer to keep my mounts and companions in light armor both because I don't think they're worth the extra money (if an animal companion dies, you just get a new one) and because the speed penalty hurts.
I'm using the wild shape as printed in the book. Why? Is there a big difference?
Yes.
