You’re doing two experiments at once.

To abstractify one level out, other than company culture and your specific wishes, what is to stop the remote employees from having to work exactly the hours that in-house employees do, and not having to answer before/after-hour calls, thereby potentially decreasing their “significant lack of focus” via psuedo-circadian/worklife rhythm normalizations?

Because I think that this is what OP is getting at, and I’m pretty sure your main response to such a thing is the general perceived lack of motivation of workers; which may or may not be wholly incorrect, I don’t know, you’re the managing party.

Still a potential psychological blind spot to look for though; take for instance:

If we imagine a hypothetical linear regression model that outlies before+after work hours on whatever litmus test you use to mentally fortify your endeavours against remote workers, what might the results be?

Again: you can’t test for two things at once.

RemindMe! 3 days