Starting a 20gal

[skabooya]

I keep going back and forth on starting up a saltwater tank. Ive been researching and doing all that fun stuff and deliberating between discus and marine for over 2 years now. Im finally gonna take the plunge and do salt. I am tearing down my 20gal freshwater tank. Still need to get rid of the plants in there. I have 3 tanks in my home all of which are freshwater planted. I also have one in my science classroom. I cant start this tank until after school is over. There is still 2 weeks left then on the 10th im presenting the science awards and then i will be supervising the provincial exams and then on the 26th i will be attending the grad ceremony. I am so proud of my grade 12's.
Anyway, i am terrified of starting even though i have done my research i feel like im going to do something terribly wrong. Im going to spend all this money and everything is going to die or im going to get apista or something nasty.
I am going to go super slow because i have time and not a lot of money lol ;P
Most of what i am going to buy will be from this forum and from other forums... or donations if anyone wants to help a poor teacher out.
So these are my plans so far.
I have a 20gal almost ready to go.
I need some sand and some LR. Im thinking about getting dead rock and then seeding it with some small pieces of LR. Letting it go for a few months so the corraline goes everywhere and the 'good stuff' is all over the tank.
Im not sure what i am going to do for flow yet. I do have 2 AC's i can use although i really like the look of those korala's i dont know yet
Im looking at the new wave 2x24 T5 fixture from ocean aquatics. Is this a good fixture for my 20H?
I am in love with zoas and shrooms. Those are the main corals i want. I may get one or two lps coral but really its not what i am in love with. I also want to get some feather dusters.
Im not sure what i want for fishies. I love inverts like little hermies and snails. I would love to get a crab as well but ive read mixed reviews about them.
My fav fav fav fish is a coral beauty but i know i cant have that in a 20 gal. Im looking at a yasha/pistol combo Or one or two active fish. I have no idea what yet. clowns are cool but soooo common. yellow tail blue damsels are neat too but meh. firefish hide a lot... i still need to think on this as you can tell.

Of course i will need to get salt, and a hydromoter, food (not sure what kind) but yea as yo u can tell im not in a huge rush to get this up and running. It will be started this summer and it will sit for a few months before i buy anymore for the tank. mostly because i dont make any money during summer

Im freaked out about starting, someone please hold my hand through this. Am i planning right? what am i missing. Please help.
Again i would like to know about the new wave T5 lighting because i would like to purchase it soon.
Thanks in advance.