Thanks, nice work with the walkthrough. I'll hold off until the seed node issue is resolved. If it is helpful, here is what I was getting when I tried to register a sub account, not sure if it is related to the seed node issue or not.
10 assert_exception: Assert Exception
rec && rec->name == account_name_or_id:
{}
th_a wallet.cpp:510 get_account
from
import_key delegate-1.lafona <owner-key>