These are the units I have (or could be) half merged or more that I never pulled for besides the first copy:
BLyn and VAlphonse are at +10. One of the copies of BLyn was from the orb pack, the rest just came annanounced when pulling for something else. Alphonse was the accident that happened when pulling for an extra Near Save copy (which ended up becoming a merge when I fall in love with Gustav).
KannaF and GrimaF are at +8. I might finish Grima the next remix, but I won’t pull for Kanna.
Second row and Lief are all at +7. SMEirika could be at +8, but I used a copy for her rally + SS3. OG Micaiah is the only one I consider a merge project, meaning I would allow myself to use 4-8 orbs on her weekly revivial if there are more than one blue. I wouldn’t mind getting extra copies of BCelica, Celica or Lief, but unless Hubert’s upcomming refine is broken, he can get the f**k off (same for SMEirika, I don’t really like ranged cavalry units).
Remaining of third and last row (+ Green Olwen that I forgot to add) are at +6. None of them are active merging projects, but I wouldn’t mind extras of them all, specially BEphraim and Myrrh. Mila and LJulia might become merging projects once they get their remixes+refines. I might also pull for them if they share with good/missing legendaries/mythics. Time will tell.
Second picture are units that are at +5 (or could be). Out of those, BAlm, Idunn, Selkie and Caneghis are the ones that might become merge projects in the future (they need an extra copy or two for me to activaly use orbs for them).