I wouldn't call it incest. Even if it is, it's magnitudes better than the situation with Nemesis.
Mikina is so far removed from Pale gentically at that point that it really doesn't matter. It's not like he's literally her uncle. From the looks of things Milky's genes were way more prevalent in the mix than Pale's. imo mothy wanted to have a Keel and Mikina parallel in OSS and didn't know how to genetically explain another miki character down the line without it being Milky's child.