[Feature Request] Vanilla and MQ of same dungeon in pool option

We have the wonderful randomizer at the moment that adds dungeons as shuffled, and then allowing us to Mix Entrance Pools.

Wouldn't it be nice to potentially have the vanilla AND MQ version of the dungeon available at the same time with shuffled dungeon entrances? Naturally, this may remove some dungeons entirely from the pool, so it would perhaps work better when there are Mixed Pools taken into account.

Failing that, Vanilla -> MQ -> Boss if no entrance rando/mixed pools for bosses. Just as a potential "extra feature" for those that want to experience everything in a stupid way.

No files, tests, or entry points are named. Start by examining the randomizer's shuffled dungeon entrances and Mixed Entrance Pools behavior, then clarify how Vanilla and MQ versions should coexist and which pools are affected. Done means the requested option works consistently, including the proposed fallback behavior.

Written by the indexing model from the issue text.