[velma]

I would say, like cypher, get just the one in one cage & if you have space keep the other cage for now. You could always use it as a play pen or somewhere to pop your hamster for cleaning. I personally like having hams at different stages because (unless there is an illness) there passing (& the cost that can incur if that is also a concern) is staggered & I don't have to face losing them all together. You can take the time to really bond with one & maybe look at another in a year, if you feel it is the right thing to do.
As for your other queries to do with cremation, burial or other that is something you need to decide which option you feel comfortable with but everyone has different ways, quite often determined by circumstance & I'm sure you will get some good ideas to help you work out what you'd like to do.