1. Yes. If they are male one of the sexiest things about being ler with a guy into tickling, and about all f/m erotica, is how clearly and undeniably turned on by being tickled the guy is when my tickling gives him a raging hard-on. If they are not turned on, I hope for them at least to still enjoy it on some level and have fun. If they don't find it fun or enjoyable, I am not interested in tickling them.
2. Yes, being tickled is a huge turn on. Especially in some areas above others, but most everywhere really. If I am going to be tickled in a session I will most likely be turned on, even if I have agreed the session will be totally non-sexual. It does matter, in the sense that if I am not turned on at all, something is probably wrong in the session or with me at that time. I have worry, sadness, second thoughts, other upsetting feelings on my mind and can't get very into it, the ler is doing something unenjoyable, going too hard, hurting me, pressuring me for sex or other kinks I don't want to do, missing all the spots I want him to get, etc. If there's no turn on to it at all, very likely something like this is going on and I just don't want to be there at that moment.
3. Not necessarily... I can find a wide variety of types physically attractive, and as ler, a person's reactions and ticklishness can make me feel more attracted to them. Of course it's great if I find them hot 😁 ... What matters more is if something about them is a big turn off. That can be a deal breaker if it's bad enough, usually this won't be a physical thing but more mental/emotional to do with their personality, beliefs, how much kindness (or cruelty) they treat others, etc. The more I see a shitty, selfish person emerging from anyone I would play with or otherwise do anything sexual with, the more I start to view the idea of physical intimacy with them as disgusting and not doable.