Thanks, @brouwerQ I like your advice of making reward account as one additional owner account. Great idea.
Just to get back to my original questions. I did some experiments, also take what @brouwerQ answered and I will summarize the answers below.
- is rewards account balance counted towards pledge? (probably no since we did not make it as one of the owner account)
Not automatically. In fact you could have reward account delegated to another pool and things will be just fine.
- is rewards account balance counted towards pool live stake?
Not unless it is delegated to your pool.
- I managed to re-delegate one of the owner account to another pool, which seems crazy to me. Is owner account allowed to be re-delegated to some other pool? If so, what is the status the original pool?
It seems cardano is pretty relaxed on this aspects. All accounts (reward or owner) can be delegated to anther pool, and current spool is still considered in good standing. Of course pledge amount will be affected and staking amount as well.