Basically the problem is the packs were bought through google play and certified by google play but weren't certified by microsoft/mojang and microsoft/mojang hasn't added a function to certifiy packs bought through google play. You are right in quoting that but I'd still expect a trade up system like if you bought it before minecraft marketplace, it would recognize that you own it and unlock it in turn. This already exists with the console editions, from what I've heard, packs bought outside the marketplace on those editions can be used on bedrock. @Jonathan Hanzel
expect others, basically anything that creates a gap below water
this kind of thing has been happening constantly since 1.10, still has not been fixed, for me, the music on the title screen starts, when i open a world it keeps going and does not stop, and then the in game music starts.
Those are individual purchases, the favorites pack was a collection of dlc bundled with a physical copy of the game. The dlc included in this bundle was not bought digitally, the dlc that was included in the bundle exists on all versions of minecraft however the record of purchasing the dlc included in pack does not exist. The problem is those who have purchased the favorites pack must buy the dlc included again in order to play something they've already paid for on a newer version of the same game.