I like the half-bracket notation for sub-claims. Particularly if the sub-claims are separated by connectives like "and”, "or", or commas, I expect it's fine to leave out the delimiters entirely. Nested claims would still require delimiters, but it's clearly better to just not make nested claims.

For multiple subjects and a common claim, subscripting each subject is indeed awkward but I can't think of anything better. It's not hard to guess the intended meaning though so it should be fine.