As mango and mimi says, the main thing is that houses have more than one entrance (something like a cardboard box house with holes cut in can solve that). No shelves or levels. Also any tubes and tunnels need to be big enough to fit both so one doesn't guard the entrance and block the other one in. Two of everything also
I think if you want a pair and have done your research then you could try it but you do need to be prepared to possibly have to separate them at some point and have two separate cages. They need to be separated at the slightest sign of squabbling or bullying.
Some pairs do live together for a long time - it's rare for a pair to live together for life without needing separating.
Pairs need to be same sex siblings from the same litter and to have already been living together when you get them - that's essential.
I really wanted to get a pair of robos also - it was a litter that needed rehoming. I spent ages trying to work out the best cage and the set up and which wheels and houses to get etc. In the end the decision was made for me as there was only one left! He lives quite happily on his own.
If you're not that experienced with hamsters then getting one might be best. If your heart is set on having a pair then read all you can about keeping pairs. The issue is that hamsters are by nature territorial. A sibling pair can live together happily unless they are in a situation which makes one of them claim some territory and turn on the other one (eg a shelf can do that). Also as they get older and hormones kick in this can happen. I have even read that taking one out of the cage on its own for a short time can make the other one territorial and not accept the hamster when it goes back in the cage. So best to always take them both out together and never separately.
I would still have liked to try and keep a pair - but you do need to have a spare cage for a quick exit for one of them.
This website has a lot of information on keeping roborovskis and housing for them
Also I have seen a tip that having one wheel syrian sized and a smaller wheel is good. They can both run together more easily in the larger wheel. And a third wheel or saucer is recommended sometimes as well.
Oak Farm Roborovskis