Would Olympic lifts be a good substitute for powerlifting lifts? If so will they be the only lifts needed or would I still need some powerlifts in there?
Instead of using just Oly lifts or just P-lifts, do all of em. Although, olympic lifts are more technical, and require a greater level of skill. So you may need to do their variations. But I'd say keep the power lifts so that you can maintain absolute strength, and gain speed strength from oly lifting. They'd probably complement each other well.
So if I do both should I do them all in one workout or should I do one day Oly other day Power and just alternate?
You could do the O lifts as assisstance exercises after you do deadlifts or squats. Or you could make a separate day for them, to hit them 100%. It's really a question of how many training days you have.
If it's oly lifting and powerlifting you're interested in, then just combine the two. True Oly lifting programs include the bench, squat, and a variant of deadlifting (RDLs). You could- One full oly move One power/hang Oly move Squat/RDL/front squat Jerk/push press bench abs **This would be a like a sample, generic Oly lifting style program where you'd feel in sets/reps/percentage of intensity.