I have a quick question. I know you can take a bus,or taxi from Fira to Oia,but have heard various things about getting from the port ( we will be taking a ferry in) up to Fira.What methods of transportation are there for this part of the trip? Thanks.

Hi

Cable Car, Donkey or taxi or walk up the donkey trail (dodging the poo).

There is a frightening zig-zag road from the ferry port, and nothing else. You can take the public bus which will be packed, a taxi, or you may be driven by the owner of your accommodation.
The harbour below Fira is where cruise ship passengers land, and they have the option of walking, riding on the back of a poor donkey or taking a cable car.

Yes, the donkeys and cable car come up only from the cruise port below Fire, not from the ferry port, which is fairly isolated and well south of Fira.

I rented a Smart Car in Santorini for one day. Really enjoyed it.