I would suggest a water bowl instead. Although if your going with bottles, the pairs that I have kept and the trio I have now, have only had one bottle before (until I moved them all on to bowls recently) and I never had any problems
Sandbaths, they simply both need to be able to easily fit in it.
As biscotti said, starting simple is best then if they seem a happy pair, you can slowly start adding things. Perhaps one thing at a time, and then you can assess how the pair seem with it, if after a while all is good then you can add something else.
Since March I have kept a trio of robos. Autumn who is 1 year old, her daughter Willow who is 5 months old and Beau, a pets at home rescue who I assume is around the same age as willow. After the initial introductions and knowing that the 3 would be okay together, they had a simple set up involving 3 wheels, a wooden arch and a big sand bath. Then they had plenty of substrate, a big open nest and scattered food. After a while like that and everything still going well, over the course of about a month I introduced a tunnel, a coconut house with 3 exits and another wooden arch.
And now, after still having a happy trio 4 months later, I am about to give them a platform and a few more things for them to climb on and hide under.
It's very much trial and error with new things! Good luck with your new little fluffs when you get them
