I wish you luck with however you chose to proceed with your older sister. If my relitives decide to meet with me, it would propbably be bittersweet as well, but I would do it for closure on behalf of my Dad and not for the benefit of myself. I wouldn't expect any kind of relationship with these people as they don't know me and I don't know them. I can't say that I would be against it, but I certainly wouldn't expect it.
All I can say is that as I've done millions of times before, I wish my Dad was here to see that I put in a massive effort and stayed focused for a very long time to find out what his true story was. Had he lived, the concensus is that he would have tried to do this himself, but he didn't, so I did it for him amd his memory.
I can tell you this for sure: had he lived EVERYTHING would have been different. For years I've wondered what I could have done to deserve this life, but since I've uncovered all of the latest info, my view has changed. My Dad had it rough. Being put up for adoption at birth, an orphan until the age of 3, adopted by less that honorable people and hit by a car and killed at the age of 32..................... Just unreal