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To be exact: there are no rewards for running seed node. There are rewards for running witness node, but since Steem is DPoS all depends on amount of stake behind your witness. Rewards are determined by number of blocks produced. As I mentioned already, with current conditions being within top60 witnesses makes it possible but not easy to cover hardware expenses (but not taking into account your time / money / effort).

Yes, you can. All you need locally is to run cli_wallet and connect to one of public nodes (regular seed node might be not enough for that as it lacks of many plugins)