Don't soak your snake after feeding. When you said you would use another tub for sanitary reasons I was taking a guess at what you meant. A soak every one in awhile can be beneficial though. Just remember that what may feel Luke warm to you is probably hot for them.

Just feed in the one tub. It will not make it aggressive.

If you find yourself needing to mist to keep humidity up then it may help to make the eco earth less dusty but I would not say mist it just to keep the dust down. I let mine dry out and stay dry.

I would suggest getting a tstat over a dimmer. A tstat will cut power if things start getting to hot but a dimmer will continue to heat which could cause the tub to overheat.