Nothing is locked on the chain. A payment channel is really nothing more than a specific type of a BTC address. So when you open a channel, you simply wire money from your own BTC address into that BTC address, that's all there is to it.
No, no and no because the only way you can move money on the block-chain is to pay the fees and
this then results in a transaction on the block-chain which then solves nothing.
it has to be locked to ensure that you can settle with the private ledger later.
what your suggesting would in fact result in two transactions on the BC if you spent $50
Bob-BC ---------------> Temp address ----------->Alice-BC
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