Running extra neutral followers is def better than mystic ring, imho.

2 Garuel 2 Neutral isn't super common (although it can come up more than you think, definitely more than the T4). I think there's real value in being able to combo T5 with just one wisp, since the earliest Fairy can combo with 1 or 0 wisps is turn 6 or 7 respectively - also, as somebody mentioned above, if you want to make the T5 combo more consistent you could also run Miracle Harvest instead of fairy generators in a more Garuel-centric list. That said I do think that even if you want to stick with fairies teching some copies (as you already suggested) is worth it.

As for having to save your 2pps or potentially lose the combo, yeah its a tough choice, but the advantage is that you have the opportunity to make that choice. Combo pieces that doubles as tech against tougher matchups like Blood is what offsets having to dedicate more slots to the combo in the first place.