They are adorable and it's a lovely set up! You may find they just nest in the digging area - our robo just digs a hole and lives under the bedding
The wheel is a good size for them both to run in together. I can't see if you have a second wheel (doesn't have to be another large wheel) but I would add one. For a pair you need two food bowls, two water bottles and two wheels so they don't get territorial over anything and can have one each if they want. They may still share things but there needs to be another one of everything available to avoid fights breaking out.
Same with houses - or have you got it more natural and no houses? If you do have a house then again I would add another one and make sure both houses have more than one entrance (a cardboard tissue box with holes cut in is fine). Also best not to have any shelves or levels (which can also be claimed as territory). It looks like a great set up to me though.
Sorry if you know all this and I just can't see. Keep an eye on them for any squabbles. What can often happen is a pair will get on fine for a few months and then when they are older and hormones kick in, they can start fighting, and severe injuries can occur. If they start squabbling or fighting they need to be separated quickly and in different cages. There are people who have managed to keep pairs successfully for life, but just keep an eye on things.
One tip I read was - if taking them out of the cage, to always take them both out, rather than one at a time as in that short time, the one left behind can become territorial.