Rainbow can be only done once. The element angelmon can be done an hour long ^^

from my experience, wind. coz wind 3rd skill = if the bear low hp, deal immense damage to opponent. usefull for killing rina in 1 hit. or any mobs.
fire i dont know. and also never care to read its skill haha.

Yes, it's wind warbear. Awaken it to unlock the skill clean shot which will deal damage to opponent equals to HP lost.

no. clean shot does damage on how many hp does the warbear lost. it means that lower current hp warbear have the more damage it does to the opponent.

Based on Hp and not hp% left. Pump HP% rune on slot 2,4,6

Example: Wind warbear got 10k hp. Enemy damaged him 9k and left 1k. He will deal 9k to enemy with cleanshot.

Then when you use 2nd skill to heal up 3k hp. Now you have 4k hp. Your next clean shot will be 6k (10k-4k)

to fuse monster a.k.a combine certain mobs to becomes other mobs

Stage 1-5 1pcs
stage 6-7 1-2pcs
stage 7-8 2-3 pcs
Stage 9 3-4pcs
Stage 10 4pcs

If B1 only you might get zero or 1 piece of the scroll only .

all useless

its 30% attack bar not dmg

when the attack bars full, mean it's ur mob turn to attack. 30% bar give you the chance to attack first.
High up arena, it matters a lot as first one to attack have the higher chance to win.