Thanks again, xeroc!
I finally managed to register an account - I'm not going to describe how I did it, but my conclusion is: MUSE desperately needs an online web wallet!
I still haven't claimed my MUSE. The reason is what I suspect is a bug in the cli_wallet's import_balance command. I've used that command numerous times with the BTS client and I've never had problems. I suspect the problem here is that the balance I'm trying to import belongs to an address that was originally from the sharedrop on bitshares-PTS. In fact all of the balances I want to import belong to PTS addresses.
I know the balances are there, and I know I'm using the correct keys. I can even look up the balances using the GUI wallet. I probably could do the import there, but I wanted to post this here first because I've seen other reports of failed or partial imports here before.
For example, the balance at object ID 1.15.52336 is such a balance. I can see it in the genesis file. I can see the balance object in the MUSE database. It hasn't been claimed yet. My 0.9.3 bitshares client shows a vesting balance whose owner is the same address as the MUSE balance object (except for the BTS/MUSE prefix of course). The vesting balance shows a PTS "sharedrop_address". The old bts wallet returns the same private key for both the PTS address and the BTS owner address. But importing that private key into the MUSE cli_wallet returns only an empty list.
Any idea?