Questions regarding Bundles

I want to publish a Minigames collection and make the different Minigames accessible individually using DLCs. However I also want to publish a Bundle, where users can buy the entire collection (Party Edition) for a fixed price (~20$). As the game will be in Early Access for some time, the price as well as the content of the Party Edition Bundle will increase over time.

How much can you modify an already published Bundle?

Like for example in the beginning, when there are only 4 Minigames, the Bundle should be around 10$ and after some time I want to add 4 more Minigames and increase the Price to 20$. Probably gonna add even more and increase the price to 25$.

Will players who have already bought the Bundle in the beginning (with only 4 Minigames back then) also have access to newly added Minigames?

Also on the Steam Shop you have this bundle option called "complete the set", where players, who have already bought DLCs from the Bundle individually, will pay a lower price for the complete set, when they buy the Bundle. Does something like that also exist for Quest bundles?

Sorry for all the questions but I didn't find any information on these topics on the docs and I can't create a Test Bundle before I publish my App.