2 people + 1 infant.
Well first I booked an international flight with United Airlines, arriving to India. They allow 2 checked bags. I think I have to pay a $200 fee to bring a 3rd. We came with 4, but, gotta throw one away. 🧳🗑

Now on a separate ticket, I'm booking a domestic flight. Air India Express or Indigo or Akasa air are my options, but Air India is the one that doesn't result in a long-layover, so I'll probably choose them.

So say we have 2 people and 3 checked bags of ~20kg each, then what's the fee?
Do any ICB (International Connecting Baggage) rates apply here, if it'll be on a separate ticket?
Do they use a total-weight or per-piece system? (e.g. Does it make a difference if we have like 15kg in 2 bags or 30kg in 1 bag?)