Would i ruin cream if i squeezed it out of a tube into a tub? and if i mixed creams?
Don't worry about dryout. You can always add a teaspoon of water, shake and let it sit for a little while. You can also leave the lid cracked to dry out overly moist cream. Not a problem.
I've revived dried, cracked, three year old soap with no problem.
As for mixing creams, the biggest thing to watch for is just chemical reactions. I'd be very concerned about mixing "modern" products with all their synthetic ingredients, but I'd feel safe mixing the kind of natural products you find most often in this community.
I'd feel especially safe mixing within one brand, cuz the chemical mix would be pretty close outside of fragrance.