hahah every question you asked has varying opinions.
if you aren't using an AMNPS then there really isn't any harm in putting something in the water pan. when I first did turkey in my mes I put a little bit of apple juice in the water pan and threw in some herbs and stuff. you don't NEED to put anything in there. nowadays I don't even have the water pan in the smoker. you really cant go wrong here just don't FILL it up with anything. its messy trying to get it out and youll basically steam your meat.
with the vent, again you cant really go wrong either way. if it is smoking very heavily then I would open it wide open. if you have problems getting your temperature to stay consistent then I would close it. I usually leave mine about halfway open. the big thing is that you don't want to trap a bunch of creosote (bad smoke) in there because it tastes nasty. so as long as you have a consistent temp and some good thin blue smoke it doesn't really matter much.
if you are knew to smoking then you probably wont taste much of a difference in either of them. once you start smoking a lot you will be able to taste the subtle flavors in each one. personally I think all hickory or all mesquite would be a little harsh for poultry. alder or pecan would be fine. or you could mix them up a little and get a little of each.
i think the consensus would say don't ever soak your chips. they wont burn or smoke when they are wet so there really is no need. some people argue they last longer when soaked. my personal experience is that i soaked chips once and i got a lot of thick, heavy, nasty smoke. so i never did it again. i just didn't see the need for it.
these are just my personal opinions. as you get more and more experience you will figure out what works best for you. when i did my first smoke ever i did a turkey and ham for thanksgiving. i was so nervous and wanting to make sure i did everything right. but honestly, electric smoking isn't that hard. its actually pretty idiot proof as long as you maintain the right temperature in your smoker and pull the meat at the right temperature. everything is pretty much personal preference. its really hard to mess up the actual cooking part.