Is this a proper intonation of question sentence?
No, no-one would say "A bheil aon phiuthar agad", people would just say "a bheil piuthar agad" not "a bheil aon phiuthar agad".
Would this better translate to 'Do you have any sisters?'?
Nope. 'A bheil peathraichean sam bith agad?' is what that would be.
Same old mispronunciation: she says "phiuthair" which should be "phiuthar".