I'm really unsure what the issue is, it seems you had it working already:
wudd disc dump made on WiiU-1: installs fine and updates fine from eShop
So problem solved...? For me it sounds as either dumpling or CNUSPacker do something wrong (changing title ID, creating a fake ticket while they should use the ticket dumped from disc instead or something like that) but why even use dumpling when you have a fine, valid WUDD dump already?
So what I would suggest to do now:
1) Deinstall the game, update and DLC from WiiU-2.
2) Run ticket clener on WiiU-2 to remove any possible fake tickets for the removed titles (that's important!).
3) Install the WUDD dump on WiiU-2.
4) Try to start the game on WiiU-2: It should download and install the update.
Does it work now? Cause if it does all that's missing is the DLC but you didn't tell how you dumped that yet.
//EDIT: Also what game are we even talking about and are there more partitions beside the game partition on the disc? These other partitions could be the DLC and/or update so try dumping them with WUDD instead of dumpling.