EAF has five A350s listed on order for Swiss and there have been numerous news articles about Swiss getting A350s, however, I can't find any reliable source for this anywhere. The only thing I could find, was an article by SamChui about Lufthansa fleet strategy where it is claimed that the four leased A350s might go to Swiss, for which there is no evidence and which would make even less sense given that the A343s will remain in the fleet until 2025 and the leased A350s are already available now and have already been confirmed to go to LH?
Last thing I heard was that a decision about future LHG fleet strategy (including distribution of A350s and 787s) would be made in May 2022.

What I could see happening is that the A343s and after the A333s are replaced by A350s, with the A343s being retired and the A333s being moved to LH or wingsdings.

I wonder what the LX A350s cabin would look like, given the size increase I would think that it will retain 8F seats, with the addition of the new PE, which would make the other cabins similar or grow a bit in size compared to the A330/340, but I wonder if LH will want to play their synergies card and have the same layout as the LH A350 subfleet with First which will be based in MUC.