Upgrading a ''''93 Hunter 27
I think that if you are handy enough and determined enough, and have some electrical and mechanical knowhow you can do all of those things. JSI/sailnet can fix you up with many of those items...just plug in the name of the item and search it. You might have to call them regarding the roller furler, but much of the other items they will have. Other of the items can be found in Defender, BOAT/US, or West Marine Catalogues.
But you should be aware that you are taking on some dauntingly difficult projects... I wonder if it wouldn''t be advisable to maybe step up in size to a boat that already has those items on it. What you want to do is going to really dent the old piggy bank!