I agree that Angrod and Caranthir are particularly at odds, and that Turgon makes no pretense of forgiving the Fëanoreans for the Helcaraxë. We are going to make a point of Angrod's ongoing antagonism (or what is viewed as antagonism) from his role as ambassador to Thingol. He is (eventually) going to spill the beans on the Kinslaying, which looks bad for the High King, sure, but mostly implicates the Fëanoreans.
So, we have Caranthir's unkind words at the council, and then we have most of the Sons of Fëanor not showing up to the Feast of Reuniting (just Maedhros and Maglor go). If we want any more opportunities to show this tension, we're going to have to come up with excuses to put them together again.
Prior to the construction of Nargothrond, the Blue Mountain dwarves don't have a lot of reason to visit West Beleriand. They *do* have reasons to visit Caranthir's halls (or what have you) in Thargelion. So, there could be a time when some of the Sons of Finarfin make the trek to East Beleriand to meet with the dwarves, and are perforce guests of Caranthir during that time. Caranthir, no doubt, would take the opportunity to be a condescending jerk about the whole thing. Aegnor and Angrod are said to be particularly close to Fingon, and Fingon would have every reason to want to visit Himring at some point, so it's possible that Aegnor and Angrod have tagged along with Fingon on a visit to Maedhros, and the dwarves and Caranthir are also visiting Himring at that time.
So we might want to do something with that, as part of illustrating Caranthir's role in Dwarf/Noldor trade. Alternatively, we could have the meeting between Aegnor and the Dwarves occur in Doriath or in Nargothrond - both places that Aegnor would have every reason to visit, and Telchar has already visited Doriath in Season 3. (Caranthir, of course, would *not* be welcome in Doriath!)
Personally, I don't think that a Fëanorean wielding Narsil would 'taint' it, but I certainly understand the desire to keep that sword in particular out of any kinslaying incidents. Rather significantly, the Fëanorean blades are not named in the histories (well, obviously Angrist was Curufin's, but Curufin didn't *make* it, nor is he famous for using it - it only becomes famous once Beren gets hold of it). Considering Fëanor was so famous for everything he made, and we know he outfitted his sons in swords and armor in Valinor before the rebellion of the Noldor, it does seem like there is a hesitance to praise their swords too much.