It is not possible to list more than one token or bid with more than one token.
Is ETH only available for bidding?
Yes, bidding support in ERC20 will be implemented in v2.
Can the auction be successful but the allocated tokens be zero?
If the participants' bids are small in relation to the total bid, it is possible that the allocated tokens will be zero, but this is highly unlikely in TemplateV1. Therefore, all participants are allocated some tokens.