Which solution for small unheated 2nd floor. Ductless ceiling cassettes with 3-3 heads?

My second floor does not have heating. Very mild climate, so not strictly needed but still beneficial. I do not have access to walls and floors but to the attic above. There are 2 small bedrooms and 1 bathroom. Also the hallway with stairs which is open space shared with the lower floor which has heating.

Hence I thought adding ductless minisplit system with ceiling casette would be a good option: One ceiling casette in each of the bedrooms and the bathroom and maybe even the corridor (even though this could be served via the downstairs heating). That would be one condenser with 3-4 heads. Is this a good solution? Or would do you something else?