As we seem to mainly agree on 2 and 3 I will answer to point 1.
Delaying the game another would have irritated the community to a high degree and was probably not acceptable for Microsoft on a commercial point of view because they needed this game to release to have their flagship game for the Xbox, it would also have ramped the cost of production considerably and would have required even more profits to balance the initial investment so I doubt having an f2p multiplayer to attract a larger crowd would have been out the question here and even if the game was paid, micro-transactions would still have been considered.
This is 2022 mate, I’m sorry but all major multiplayer games have micro-transactions and are subject to be or become f2p at some point weither we like it or not, personally I don’t mind it, I’m used to it and I know they won’t necessarily impact the quality of a game.
I’ve played a lot of TF2, CSGO and PUBG when they were paid games and free 2 play games and I never minded their economical system because the games were enjoyable without paying (TF2 got out of hands at some point but it died of age more than of any commercial decision Valve made with it).
I also play a lot of MTGArena a game that some consider to be predatory but I’ve been playing for 2 years now and only threw 20 bucks into it without feeling much left behind…
I like Halo Infinite’s multiplayer’s gameplay experience and I can enjoy it without paying even though the game is a bit in a content drought lately, I don’t really care, I’m patient, I go play other games while Infinite gets the content it is supposed to have to entertain me more and still play the game from time to time to have fun with friends…
I’ll give a little precision on your point 2 tho, people who work on MCC are also competent enough to work on Infinite, so it divides the taskforce even if obviously they are 2 separate teams, they could work on Infinite because they have the skills or could relatively rapidly acquire them, I don’t want them to work on Infinite tho, I like to see MCC being supported, but that’s just another bill to pay for 343 to ensure their service and it surely isn’t free for them…
Also regarding your point 3, I personally got into Infinite relatively recently because I had no proper device to play it before that, so I don’t see the content drought in the same harsh view as you do, but I’m sure 343 will deliver, it just takes them time and I can wait and play other games in the meantime because that’s what I do, I rarely focus on only one game…