Tbh there's alot that doesn't make sense.
Office worker picks up most client queries, which suggests the role has a lot of face to face communication. In which case, how did the higher up allow someone who lives 200 miles away to be given a job? If there's lots of client face to face queries, it makes no sense any of them are at home.
If its phone or email queries, technology allows for these to be divided up equally. I suspect these client queries are few and far between. Op seems far more concerned with the office workers feelings, than the rest of the teams feelings.
If Ops manager really thought they could force the staff back to the office, they would have done. Which means they either arent that bothered, or they can't.
Having them all in the office isn't a guarantee of good communication. Plenty of offices are full of teams that don't get on and are better apart. It could easily get worse.
My experience of managing office based, hybrid and home based teams is that the ones who take the piss at home take the piss at work. Instead of doing washing or going for a walk, they go make coffees, stop by someone's desk for a chat, go to the toilet then come back 25 mins later then start it all over again an hour later. And when it's right in front of someone's face, then it causes more resentment.
Op your senior managers need to tell you why they haven't enforced regular office work, why they employed someone so far away and what their working agreement is, how long these people have worked like this, why they actually want them back (team work, collaboration, community aren't reasons they are buzz words), look at why you want them back. And you need actual reasons, not buzz words too.
And it can't be because office worker is lonely or the worker far away might not be working when they should be. Then look at othwr ways you can improve your management, it might be technology to see if people are available when they should be. It could be accepting output is more important than input and despite people not always being at their desk, they are achieving the output. It could be just speaking to them individually and communicating your expectations.
Then look at what options you do have and think about what happens if all 3 had their notice in. What's the back up plan?
But you also need to think about what happens if 1 or 2 come back in and what that might do to culture if they do it but aren't happy.
I have seen it at my own work where a team was forced to come back in because their output was poor. Really poor. Its actually negatively impacting anyone else who is in, on a given day. Because they re all so negative, bicker, moan about each other/customers/other teams etc.