As an Aran

do you have the possibility to pot between two attacks and maintain the combo?

Yes. You have 3.5 seconds to maintain your combo, and you can easily pot in that amount of time.

Combo as in the little numbers? Yea. Combo as in Single -> Double -> Triple Swing? I think so, although it's been a while and I lag a bit in kMS.

You can pot, pick up items, and keep comboing. Unless you're me playing MSEA, in which case you can pot, pick up items, then watch as everything moves in place for 10 seconds and ruins your 300 hit combo.