As others have said, now is not the time to buy an AR. I search the web and just LOL at the prices these days. Not to mention the price & availability of the ammo.
I own one of each and both the SKS & AR15 have their merits. It would be tough to give up one or the other. The AR is a bit more accurate but the SKS is just plain bullet proof.
My thoughts on your situation... I would sell your least favorite SKS for as much as you can get. Then save the money for when the current panic subsides and you can get an AR for a reasonable price. Those SKS's will do anything needed, from SD to hunting for food in the meantime.