Interesting, though one problem with your suggestions is that you put down the idea of Golem getting a Mega because it has Alolan Forms yet then say Raichu is likely even though it too has an Alolan Form.
Anyway, just want to note possible other reasons for re-filing:
Raichu & Eeveelutions: Easy, they're the evolution of the Starters. They may be planning on doing something special with them. In addition Raichu is Lt. Surge's ace.
Arbok & Weezing: Jessie & James' aces.
Persian: Giovanni had Persian made into his ace in Yellow because of the anime. Though... Mega Persian or Giovanni which makes at least the Kantonian Persian into Normal/Ground or pure Ground?
Golem: Brock's ace.
Starmie: Misty's ace.
Dragonite: Because it's Dragonite.
Not sure for the other's though. Machamp in my opinion is prime for a Mega. Not so sure about the Hitmons though, to me their kind of the oddest choice on their. Not that I can't see what their Megas could be, but would that be too many new Fighting-type Mega?
As for the missing Fairy-type, I see two possible choices:
Mega Jynx could become Ice/Fairy, just give her Moonblast or Dazzling Gleam and she'd be good.
Mega Dragonite could be Dragon/Fairy, its Flying-type never really did anything for it and it wouldn't be stepping on Mega Altaria as it's more balanced/defense focused.
Also I'd be careful what you say about Jynx,
there's a member on these forums who is a BIG fan of Jynx and will adamantly defend it...
Maybe if we get them to get out all of their Gen I pandering in these games they may get tired and finally move on? This could re-invigorate their interest in Mega Evolutions overall and maybe in Gen VIII, since they did a lot of Gen I in LGPE, they'll focus on other gens in those games (not to mention we have remakes, notable Sinnoh and Unova).
Who uses Mega Audino? When people think Unova they probably think of (not counting Starters and Legendaries) Zebstrika, Excadrill, Scolipede, Lilligant, Krookodile, Darmanitan, Cofagrigus, Archeops, Garbodor, Zoroark, Cinccino, Vanilluxe, Galvantula, Ferrothorn, Klinklang, Chandelure, Haxorus, Cryogonal, Golurk, Braviary, and Hydreigon. Audino isn't really on the top of the radar unless you're grinding for experience.