I don't know that it's out of reach, but I don't know that I think it's all that likely.
The Pairs alternates list for the GP includes any and all teams that are achieving the total score minimum at the early Challengers, so it now has 11 teams on it and 2 more competing at Finlandia this week. It might come down to which fed is doing the inviting as to whether or not Efimova/Blommaert can get a second invitation - eg, if Chernyshova/Windsor do wind up withdrawing from NHK because of his ankle injury, Japan might decide to invite their new senior pairs team, Yunoki/Ichihashi rather than the top scoring team available on the alternates list (EfiBlom).
As far as making the GPF - again, it would really depend on where they wound up at for a 2nd GP. The fields at GPdF and Espoo are really strong (SDDes, PengJinx2, SafBerux2, HocKun, GhiAmbrx2, SmirSiia), slightly less so at SkAm & NHK, and comparable to SCI at MKJW. If they were to get a 2nd assignment at MKJW, then, yes, I'd expect that they could easily qualify for the GPF, but my guess is that some of the other teams waiting for one assignment will be invited first before any of the teams on the alternates list get a 2nd assignment.