1) The only card rulings that could be somewhat ambiguous are R&D Secret Lab and Mishra's Toy Workshop. I'm tempted to effectively ban the lab by ruling that only the gatherer text is used, not any original card text because it's a mess when you specifically ignore clarified card rulings. For the Toy Workshop, what you spend the mana on has to directly put a token into play, not potentially do it later.
2) It wasn't banned at the beginning of the original thread and yeah, it's just a lotus with an extra mana that can't be recurred.
3) Yes but I'm ruling that it loses unless the person who plays it provides an example of a card they choose to mimic winning (unless it's an obvious vanilla card). If they can search it and find a winning one, fine but I'm not looking through all of them myself. Especially when with Fae of Wishes and a sideboard of 3 cards, you've got up to 6 different mana costs you can work with (depending on how you treat interactions with Garfield and adventure) and cast when you have a blue storage land. I doubt many decks would let you get there but if they do, it's on you to find a solution.
4) Correct, those cards are only allowed in special rounds at this stage.