Interestingly enough, while conversing with Mighty Man, Charon referred to Evinlea as a member of the First and stated that there was an entire world filled with beings as powerful as her. No mention of a power up, no ligil, nothing.
First can be charged up simply by being in a place rich in energy (they are strong on Elysium than off, for example, or on Mystic's world) and can lend each other power as well (which is how Ingra leader of House Sinister runs things, her entire council gives her some, making her the strongest of the First at the time).
I'm not saying he altered her power or changed her type or anything, just lent her some to raise her charge level in the normal way, 'topping off her tanks' so to speak.
As she could process Negation power just fine at that point, it'd be trivial (heck, it might've been done when they 'sealed the alliance' in that huge burst of energy).
On another note, if I replaced Evinlea with Gammid how well do you think he matches up with Norrin? Or do I need to bring Qtzr in?
Gammid totally lacks the flexibility and power (his energy blasts are strong and unlimited in quantity, but not planet-busting). Unless his sigil can drain Norrin of the power cosmic (which I don't think the merged ones really did. The two-comma kinds might be able to pull it out), he's in big trouble.
I think Evinlea's fine, but if you did switch Qtzr would be fine too, I'd probably go with team 1 in that case (though teamwork would be worse).