Definetely.
if you want
Yes.
Yes.
Yes.
Totally.
Absolutely he would defeat him in one attack.
Yes.
No because there are 13 Knights verses one Eden you can only guess what happens to Eden!
Yes.
I would say yes cuzz ultimecia has 4 forms jenova only has one.
Yes.
They're of different games, no real way to find out, sorry.