I think you're right about Rhys and Janto. I read a lot of 'poor Ianto' fics, but Ianto is one strong BAMF and I can really see him impacting Jack in a very postitive way. Jack needs someone who can see past the facade, and Ianto is the one.
I agree about RTD as well. If Gwen is his idea of an ideal woman, there is no hope for him, I fear. :) Like so many fics where Gwen reminds Jack of Rose, maybe Eve reminds RTD of someone in his life and he is recreating her. If so, I feel sorry for his bad experience with whoever she was. The one that so distorted his idea of what a good woman should be.