Is Bittrex going to honor the ZCL hodling and auto-add the ZEN?
Yes today or tomorrow we will make that happen. Though I'm not sure why they would honor anonymous coins now that darknets markets announced that they are dropping support for Dash. Regardless, Zencash will become much more valuable once a new revision of eleos wallet supporting ZEN comes out. I expect things to pan out when there's an update.
As soon as Bittrex confirms to the ZenCash core team that there will be support for the Zclassic and ZenCash chain split we'll post an update here. Not making any promises until there is firm commitment.
Here is a guide on how to move your Zclassic off Bittrex onto your own wallet, export Zclassic keys, then import them to the ZenCash wallet:
https://blog.zencash.io/transfer-zclassic-to-eleos-wallet-and-copy-private-keys/There are other ways to export Zclassic keys from your wallet and import them into a new ZenCash wallet also, of course, the above is just one example.