Re: transferring your current tank to a larger one, yes you can move it all. It won't have tp be precycled if you're moving over your filters. May as well use your current filters if youre moving over your fish. IMO What you'll want to do is read about how to quarantine your discus when they're bought. You won't want to introduce the discus to the cycled tank right away.
Swords and crypts should be fine at discus temps (>82 deg).
You can get sand at home supply stores like lowes or Home Depot. Or at a pool store. You can add it in later if timing doesn't work due to the season but its a pain.