I've never seen a family member on here but I did find various pictures of my ex-girlfriend on TMF and one other site. We talked about it for a little while and then everything sort of died down. It's probably for the better.
Some women may have ticklish breasts and some may not. I've seen plenty of tickling videos that show women with extremely ticklish breasts and nipples.
I think it's a three-way tie between my feet, sides and armpits. Spider tickling is a great technique; very effective from my experience.
As far as how long I could last, it all depends on the scene and intensity.
I think Tickle Abuse does a fantastic job, easily my favorite out of the bunch. Even the more recent videos are damn good. I like torturous tickling, just as long as the 'lee is enjoying it (somewhat.) I want them to suffer and squirm but only in fun. No tears and/or unhappiness.
I have two: Scar 13 and Lexi Belle (I know she's done some light tickling but nothing major.) Both are gorgeous and would look stunning in some bondage and tickling senseless.