If you have zero Minato fragments, then its a doubt. Its not bad to get Minato 4 stars, but if you do not have good support ninjas for him it won't be that good.

It will all depend on what Fuku deal gives when the next appears. Since you have relatively many Bee and Kushina you can consider making them both 4 stars and using both in 1 team. They work really well with each other. Ofc, Minato is the second best carry in the game after BT Madara 10, but if I were in your situation I would prefer having Bee and Kushina 4 stars on 1 team than Minato Edo 4 stars with no good ninjas to support him (again by considering all the resources you have and which ninjas are close to recruit and which are not). Sasuke Rinne is good, but he needs a specific team and will be good only after BT and you are not close at all + Kushina nowadays is not that expensive. In 1v1 Kushina is often stronger than Minato if BP is equal and you cannot control her with Kurenai or Ibiki. Either way, its your choice but it will depend on what Fuku gives. You should probably wait till next Fuku and if it gives someone who is close to recruit for you than you should think and consider and ask again for help. Because now its all theory and speculations about next Fuku which we do not know what will give.