[Arran]

Fisher branded 12AX7s are probably near the moon, but Fisher didn't make tubes they just rebranded ones made by someone else. Mullard, Phillips, Amperex, and Valvo 12AX7s are all the same, but for whatever reason, much like with the Sprague orange drop caps people seem zoomed in on the Amperex and Mullard ones just because of the water based ink labels. You can use Russian/Soviet 12AX7s, the Fisher won't know the difference, or good testing used ones of any brand.
  If you want to save some work, and some money, leave the mustard coloured Phillips caps alone, those rarely go bad, but stick with replacing the dog turds and the electrolytics. I'm not sure about the transparent ones, I believe that those are plastic film caps, possibly polystyrene or polypropylene, so they might be all right. Some guys on various forums shotgun everything when there is no need to, guitar players have a similar mindset when it comes to tubes thinking that it makes their amp sound better. Those parts kits look like a ripoff to me, just generic yellow film caps that you can get anywhere, and I don't know about the electrolytics but if they are off branded stay away.
   I'm actually surprised that nobody is making repro Fisher knobs of at least some types, I'm also surprised that they were mad specially for Fisher and were not simply sourced off the shelf from a plastics molding firm like Kurz Kash or Amphenol. What makes them so special, the colour or the trim?
Regards
Arran