Title says it all. Does it have to be six separate Toa? After all Krahka can mimic Toa powers and create or break a Toa seal too so why wouldn’t the same be the case for two Toa Kaita?
Depends if toa kaita could use their elements at the same time. If they can only use one at the time then no
I think they can:
“A Toa Kaita also possesses greater elemental power than its three component Toa, and can wield the powers in combination.”
So then technically they can make a toa seal.
Based on what we know, yes they can.