i know that Edea already had sorceress powers , but what good does it do for Ultimecia to go back and time and give it to her , when in the present, Rinoa has it now ?
I don't understand, sorry. Could you try and rephrase that(don't hesitate spelling it out for me).

if that meeting did end up altering the present , then does that make Edea still a sorceress
Not as we see her in the end of the game, no. But it certainly didn't change anything, so it doesn't matter.