1) As with most upgrades it really depends on opponent, strats and schemes for me. I have tended towards Rising Sun and Woke up with a Hand. I also tend to avoid Wanna see a Trick because you lose the aces (and for some things you want to keep those aces). This is definitely your up front Huggy approach, and it does mean that Lynch has to be up front a little bit in order to take advantage of the respawn. Look at taking Endless Hunger more when there is something like Assassinate in the scheme pool, as it allows you to use Heed My Voice to remove the models that are gunning for Lynch. Murder Protege can be countered by Rising Sun, but only if you don't have any other Henchmen kicking around in your crew. Really the truth is look at the scheme pool etc, and who you are playing against. There are uses for both limited upgrades, and over time its something you can figure out easily... I will say that when you start with him Rising Sun allows you more time to get used to Huggy, but it is sometimes difficult to get the respawn condition.
2) When you activate him is really open to situations. I "tend" to activate him last for the extra cards. I have also activated him first so that Final Debt kicks off twice in short succession (the 2nd time post giving Brilliance to my target with the pistol).
3) No. If he flips or cheats an ace (why????) then it is gone.
4) Terror Tots, get that ace of masks in your hand and watch them run any scheme marker drops you want them to. Infinite successful sprints is hilarious. Beckoners, use them to pull your models forward in the first turn, mess around with opponents models there after. Depleted, tarpits, do what you can to get as many things around them as possible, and then shot them yourself to mass infect people with Brilliance. Doppleganger!! Copy lure, copy tendrils, copy Final Debt!! I'm currently running Hannah as well for similar reasons.
5) He is a lot more general than Pandora certainly. I play Pandora a lot and she is a lot more selective on Strats and Schemes than he is. If it is marker heavy and you take tots he has it covered (with a little bit of card hunting anyway). If its attack heavy than you can pick up models to handle it and Huggy and Lynch can then just center point the attack. He can cover most things with some work.
6/7) As others have said, use Beckoners. I only take one, but the Doppleganger and Hannah can then copy Lure and do the same job (though the aren't as good at it without the trigger the Doppleganger can do it more often so there is a balancing act to work on here). Graves as well (also already mentioned), he isn't specifically weak, he's just picked on a lot.
8) Yes, could be handy. At the moment I don't have them to try out. Not sure how much you need the range, but having so far not played any crew with much of a ranged option in it, its probably lack of experience that limits my advice here.