The Gods have listened to my prayers.

You really want to know?

OK my method as follows - but bear in mind I'm using the Origin version (now the EA app version) not the Steam version.

1) Completely uninstall the game
2) Delete all folders pertaining to Dragon Age Inquisition from the game install folder and also the 'My Documents' folder.
3) Re-install the game.
4) Launch the game once, normally, from EA Desktop client
5) Shut the game down.
6) Shut EA Desktop app down
7) Install and launch the latest version of Frosty Mod Manager in Administrator Mode and wait for it to set up and do it's thing.
8) Install the mods you require
9) Shut down Frosty Mod Manager
10) Install the Datepath fix from here:
github.com/Dyvinia/DatapathFixPlugin
11) Delete the file called 'Launch Platform Plugin' from the Plugins folder in Frosty Mod Manager
12) Delete the folder called 'ModData' from the Dragon Age Inquisition install folder
13) Launch Frosty Mod Manager
14) Wait for it to do it's thing
15) Launch EA Desktop App
16) Launch the game from Frosty Mod Manager
Voila!

I should also add that it seems to be necessary to launch Frosty before launching the EA app. It shouldn't make any difference, it makes no sense - but there it is.

The latest version of Frosty can be downloaded from here:

frostytoolsuite.com/downloads.html

Finally, I've been able to get some - not all - but some DAIMod mods to run either with Frosty or concurrently via running Frosty and DAIMod at once, which involves a load more hassle and folder deletion/renaming and probably more hassle than it's worth.

To run a DAIMod in Frosty, simply unpack the RAR or 7Zip file and install unpacked the contents into Frosty, it won't work if you just try and put the RAR or zip file directly into Frosty.

Some work, some don't. Anything that contains new textures, or has a configuration menu probably won't work - that said I did manage to get More Fade Touched Materials to work.