1)do miners process and verify transaction? what happens when all bitcoins are created, so there are no miners to maintain the system?
Miners are compensated with both tx fees & the block subsidy (new coins). As the block subsidy declines tx fees will become more important. "Mining", block creation and verification will never stop.
2)is it possible that the originator of bitcoins made a bunch of coins for himself before they became popular and others were verifying the code and creation of a limited number of coins? could satoshi have an unlimited hidden stash of coins?
No. Bitcoin is a public ledger. Every coin ever created is known any unknown coins would be rejected by honest nodes as invalid. It is very likely Satoshi mined a lot of Bitcoins, how many is subject to some debate however for roughly the first year the hashrate on the Bitcoin network was very low, even a single average personal computer could have mined a small fortune.