2)After all the blocks are minted, the network, as I understand it, will be responsible for validating transactions, and will receive occasional transaction fees as an incentive for running the system. Currently, generating coins guzzles CPU cycles, but I can see no reason why the much faster transaction processing won't be far more lax on the CPU, as it won't involve literally constant crypto work. Am I right or wrong here?
You still need to generate blocks (and do all the hashing etc) for transaction processing - the proof-of-work is what prevents an attacker from producing a very convincing block chain with transactions cleverly rearranged to undo his payment.