Yes they removed the profile only writable volume. You know only have the UIA + Profile or UIA only. (UIA = User Installed Applications).
I would not suggest using a mandatory profile with writable volumes. If have no idea if it will work but as per Appvolumes recomendations you need to have a local profile. The profile is being loaded the moment the writable is being attached.
We also tested a profile management solution besides UEM and for as far as I can see you can use both of them together. Only thing is that your best use case for this is cross platform sync of user settings, VDI, Notebook and Desktop for example. If you have an all VDI setup I don't see the added value of using borh writable with profile and UEM.