I've puts Dodgerunner's tension kit in my fiero as per his supplied instructions. It was straight forward no problems.
I recently replaced my water pump and I was able to do it all from above (other than the coolant draining that is). It really wasn't that hard to do like that. I never removed the tensioner or alternator during the water pump change out. Taking them out may help but I didn't find it necessary. Also in my experience the alternator brackets are a bit brittle and can break (& have broken

) when worked with. So I prefer to leave it alone if possible.
The most important thing you will need for the job is patience, don't be in hurry, clean, clean, clean the gasket surfaces and it will all be fine. Beer can help if consumed at the right rate too