you most certainly do not need a relay to have just one fan to work. Right now, I just have the one disconnected (two prong plug).
And for right now, until I get a temp sensor and relay in, I am just going to throw a switch in. I'm not sure if there really is a problem with such a setup (unless you are forgetful, etc.) Every time I do get into the car I switch the fan on and go. I never had a problem in the past with forgetting this (had a switch put into my camaro a few years ago). This isn't, by any means a permanent solution, but for now it will get the job done.
The car is a '87 GTA, Carb'd 350. As far as I know the fans are the stock ones.
And again, thanks for your help so far!