need help upgrading a 2.5 gallon to a 5 gallon nano

[Skeptikal]

Im getting tired of my 2.5 gallon experiment. Its currently housing two turbo snails, an orange legged hermit crab, a porcelain crab, a dart goby, some kind of 3 inch worm (it looks like the worms from that trench in the king kong remake, same mouth parts, spends all day filter feeding) and this weird bug thing that also came in with the live rock that nobody can identify. Its been a great learning experiment, but its too small to put any coral in, and the current denizens hide all day. Super boring. I picked up an acrylic 5 gallon lizard/frog keeper today, mostly because I liked the shape compared to a standard glass rectangle. This should give me enough room for bigger, more active fish (even though I am partial to adding more, larger inverts). I want to turn the 2.5 into a sump and possibly a refugium, but I've never had any sw tanks bigger than this 2.5 gallon before, so the concept is new to me. Can anyone detail that I will need to turn it into a functioning basement sump?
Also, I am going to outline my plan for setting up the new tank and transferring livestock.
1. wash new tank, add new (dry) live sand and base rock
2. add seawater, (the bottled stuff from petsmart)
3. wait until it clears, add old filter cartridge from current internal filter as well as live rock from lfs.
4.wait for it to cycle (one week approx), topping off water as needed (its dry here)
5. move internal filter, old live rock into tank as well as the livestock
6. configure old tank into new sump (adding whatever equipment you guys say I need)
7. slowly add new livestock and corals
8. crack a beer and enjoy the tank

Does this seem like a good plan? Is there anything I should change?
Im really excited about this.

 

[PSU4ME]

Well your plan doesn't sound bad but upgrading to a 5 gallon from a 2.5 gallon isn't going to do much and I don't know how you'd use a 2.5 for a sump.

Having a tough time visualizing this. Any pics?

 

[Skeptikal]

ive decided the sump is just ridiculous, and too expensive to bother with. I was also talked into moving into a 10 gallon instead of a 5. Ive got everything I need except a heater and a light. I really want to do a crustacean tank, most likely with an arrow crab. It was recommended to me that i use proper marine lighting, so I'm wondering if i could use marinelands 11 inch led light bar which also has a moonlighting feature. Would that provide enough blue light for crustaceans and maybe some mushroom corals? i can still put up a picture of my current tank if you'd like.