1- If you see them "cuddling" together, they are not. They are competing for that spot and dominance.
2- say you find poop with worms, poop with blood OR a regurged feed...... Who did it come from?
That all I have to make you think about.
Can they cohabitate? Yes BUT most people are not capable and I don't see having the risk of extra stress worth more than the $13 it would cost for two 28qt tubs.