So I don't know anything about modding or if this would even be possible, but I thought of this idea for a change to the map's formula.

What if instead of waiting for the other bosses to finish their attacks, each boss could be on separate phases at different times, so you could actually focus on taking one in particular out early if you wanted to. It would be more chaotic due to the lack of rest periods between phases, but I think it'd be a fun challenge!