Yes, it's good.
Yes, it's good.
It works well as is, suitable for gaming without needing a high-end CPU. 10400f is fine.
No thought at all. Never looked into that board lineup before. Just search online or watch videos for suggestions. https://www.wepc.com/reviews/best-h410-motherboard/ The Gigabyte H410M and H410M Pro seem to be in demand, along with Asrock and MSI versions. All three should perform well for gaming.