comma/on the drums

Are these sentences correct:
[color=red]1-Harry was in a rock band together with his brother on the drums.
[color=blue]2-Harry was in a rock band together with his brother, on the drums.
(I think in 1 the brother plays the drums, but in 2 we can’t tell whether it is Harry or his brother)

[color=red]3-Harry was at the party wih his brother in his pirate costume.
[color=blue]4-Harry was at the party wih his brother, in his pirate costume.
(3 and 4 sound a bit strange to me. If they are correct, I think one can still not tell who was wearing the pirate costume in 3 or 4)

“Harry was in a rock band together with his brother on the drums.” – ambiguous
“Harry was in a rock band, together with his brother on the drums.” – his brother played the drums
“Harry was in a rock band together with his brother, on the drums.” – to me this means Harry played the drums, but the sentence feels awkward

“Harry was at the party with his brother in his pirate costume.” – ambiguous
“Harry was at the party, with his brother in his pirate costume.” – his brother was wearing the pirate costume; ambiguous whose costume it is; “with” has a vaguer sense in this sentence
“Harry was at the party with his brother, in his pirate costume.” – to me this means Harry was wearing the pirate costume