Could I use the pools if I paid the resort fee if I don't stay there

No, you have to stay there. But if any guest is staying there who is known to you, you can use pool for FREE !!!

If you own at Orange Lake you can use the facilities even if you aren't staying there. We go there when we visit Lakeland all the time

I don't think so. I believe you have to be staying on the resort.

I don't think so, unless you an member