A long way from a salt lfs

Hello all, allow me to introduce myself. My names Alyssa and i have had
tropical fish for the last 5 years now, mostly angels and bala sharks. I've
had more angel babies then i can shake a stick at and i decided to challenge
myself with a FOWLR 20 galleon tank (my 45 has my angels in it :-) ). So we
have established I'm not a huge newbie... just a little one *wink*. Lotsa
research on the net other the past 2 weeks which, of course, has some
questions.....

1) I live 5 hours away from Edmonton where the nearest sal****er lfs's
would be. Anyone else in the same predicament? and how did you manage? I go
there like once a year so what's you experience with mailorder... or ebay?

2) Is a protien skimmer an essential? Like i can't live without it. Anything
I should be looking for in particular? Once again, what about buying second
hand (can we say EBAY) *lol*

3) I read that you shouldn't use aquarium epoxy-coated gravel in a marine
steup. Why is that? Can i use beach (sandbox) sand? I have that with my
freshwater tank, and there is no problem.

4) What is the lowest the salenity (spelling?) should be at? One place says
1.018 at the lowest, another said 1.022 at the lowest. Is it that much of a
difference?

5) I would like to end up with these species (not sure how many of each i
should try for)
Yellowtail Blue Damsel, Yellow Tang, Goby (not sure what kind,
recommendations?), a clown fish (nemo), and a cleaner shrimp, starfish. So
good mix or no? I read that with 4 W/gal of light at 10,000K I should be
able to grow some polyps and mushrooms, agreed?

Tanks for anyone who even reads this! I appreciate any help. I originally
wanted to get seahorses since that's what sparked my interest in sal****er
but decided they weren't the way to start off in a new hobby. (a friend of a
friend is the second person in Canada, supposedly, to breed them). Very
awesome. Thanks again for the help!