Yes... but maybe not now... given how they also include dwarves in Gondor now... LOL. And there is enough on their plate already and big expectation here with a place like Umbar as it is, without throwing dwarves into it as well. But yeah, this is something that would be neat to explore eventually, if they could justify the Southern dwarves somewhat interestingly, since - I assume - Abnúzhu were never in Harad, or... where they?

Well, that's certainly something they could play with. I noticed this before, that the situation with the clans is a bit weird, and it's unclear how the Eastern pairs were placed, originally:
Which is confusing enough and leaves some room to make sense of it, besides - Longbeards themselves were scattered like from Ered Luin to Iron Hills, so not unlikely for some of the others to be as well, with many different dwellings, rather than just static. Maybe it's not unlikely that they all originated in Orocarnii but the pairs were placed further away from each other, and Abnúzhu colonized Mordor's mountains from their Southern dwellings of Orocarnii and then that branch colonized even further into Harad and then was cut off when Sauron arose. Or maybe the devs just wanna put one dwarven pair in Mordor, initially, since that would qualify as "Eastern" mountains yet wouldn't be Orocarnii, or maybe they just wanna come up with brand new smaller mountain chain East of Harad. There are some options here.