You need to upgrade to Aem forms on JEE stack.
Do Workbench process convert into AEM workflows?
The lca will be deployed as is and will be seen in workbench like earlier version.
Are PDF XFA forms used as Adaptive Form Templates?
Yes, you can use xdp template.
Can I use Adaptive forms with Workbench processes?
Yes, you can.
What else do i need to transfer?
Custom components, data and lca.