a pending tank change is not urgent... or extreme.... though very hard to do for the first time.
yes you can transfer everything but the results may not be satisfactory. once you disturb an established sand bed... any thing may happen nothing, nitrate spike, amm spike, PH shift, O2 dep, who knows. the worst I have ever expirienced in a tank change over is an algae bloom. but it was always bigger tanks, than what I had before with a more restricted feeding schedual untill I built up to an established setup.
may help may not