Question should be masked man or jonin minato.

You can get sage naruto by seal scrolls or free draws.

Depends on your play style, control or damage.

Frankly, I prefer masked man over jonin due to his control and his array of skills is unique. He can stop a team that relies on buffs or root of warrior such as lightning wind blade asuma and the high growth rate iruka

If you plan to spend in the future, just get hokage minato. I heard he will get skillbooks in the future.

Jonin is more like a glorified temari swimsuit(a future ninja which can be obtained at a cheaper price)

But the decision is up to you.

About gakido, he might get skillbooks in the future because ningendo and animal path recently received these additions in an older server.

But out of all pains, he is one of the most useful due to his skills.