I'm a bit confused - Seraph already does not consume any resources, unless I'm missing something you're proposing?

In regards to Dissipation: locking the functionality behind Seraph would make the button even worse, in my opinion. If it doesn't give Aetherflow, you're just taking away your enhanced Embraces/Consolation for a party wide Esuna by using it, which would then need to be balanced around or else Scholar would become incredibly valuable for the little mechanics that require Esuna and Dissipation would be otherwise completely useless in content that doesn't need it. Why would you ever want to get rid of Seraph early unless you really need Fey Union? What makes up for the lost DPS/healing that Scholar could've done with Aetherflow gained from Dissipation? Also, what now becomes Scholar's level 60 capstone? Do they just lose another ability only to get it back at higher levels?

For Eos and Selene, why would you want to tie a resource to their summoning? To encourage pressing the button more? I agree that they can really just be merged into one button that lets you cycle through who you want, but why turn their button into "Aetherflow but for Faerie gauge"?

I also really don't think filling the faerie gauge is particularly an issue for Scholar, as it stands you will regularly be capped on it in ShB due to how Scholar works. Perhaps in EW it will actually become a resource that you manage more frequently due to the ability to weave Fey Union, but I believe it will still be regularly filled up and won't exactly be something you'll need to worry with. You haven't proposed anything that would use Faerie Gauge, so it would still be just Fey Union?

You also say that "Dependence and reliability on the Faerie Gauge will be increased overall."
But I have to ask - why? The gauge already feels hastily slapped onto Scholar's kit and you don't interact with it outside of two abilities that are about to become one again; so what would warrant Scholar being more dependent on one ability?