I see that you almost made an existing card with one of the customs in your imgur:
murmuring bosk
remove the weird tribal wording and come in untapped and it is really nice. (basically add "swamp" to the custom in the imgur)
If you go with B, just add a sac outlet to provide use later in the game. MTG already has a 2 color variant of this that proves itself to be quite good:
horizon canopy
So it's not exactly the ratio stated lol. About 2% less land density than stated by ravnic. Also not a standard draft experience. I think ravnic was speaking to both of those staying standard.
You covered almost every card I currently run, but there are a couple that you didn't touch on
skyclave shade
god-eternal bontu
phoenix of ash
multani, yavimaya's avatar
master of death
Blue does have some good options if you are pretty deep in the GY themes
skaab ruinator
vizier of many faces
Yeah the fact that you can get the T2 loot is a big upside over just playing Merfolk Looter. And of course it has the ability to transform into an archivist later as needed.
I don't think it would be that big of an issue, especially if Chris has used it in actual play and not had any bad outcomes.
I honestly think it's fine both ways. One way prioritizes the mana ability, one prioritizes the activated ability.
It's rarely if ever come up for me. I supply tokens, dice, marbles, coins, and a variety of other objects for my players to use according to their preference.