Alternator Troubles? '03 Outback

For starters, I have a 2003 Subaru Outback (base wagon). She may not be
fancy but she has been a sturdy reliable car so far.

So I have had some small electrical issues (described below) and a friend
recommended I get the alternator tested. I did (at an Advanced Auto) and
while idling it would fluctuate between about 13.65 and 13.9 (when idling for
roughly 5 minutes)

Should I replace that Alternator?  (Also what should it read so I know for the
future)

Minor electrical issues are:
-->Powered side mirrors no longer move (both driver and passenger side)
-->Heated seats work some of the time (some days it works, others it
doesn't. Most days it no longer works)
--> The small lights in the front seat no longer work. (I have already
exchanged light bulbs in those that I could easily reach)
--> Lastly (and most recently) the powered seat controls on the driver's seat
have stopped working

I should also note that I did check the fuses, and they look fine.

If the Alternator is fine, any ideas on where I should look next?