I am editing a project with variable framerates (5/8/25/50) the base rate for the project will be 25.

After trawling through most of the forum posts in relation to management of such tasks I have been unable to find anyhere dealing with non-standard rates such as the ones above. 

My issues are arising primarily with the 5 fps footage. Each shot plays in the source monitor for approximately a quarter of their runtime before displaying a black screen with ... 

'Exception: SFPlayConsumer:Execute TIMEOUT'

... makes sense with avid automatically converting the clips to project's 25 fps settings.

I assume they should have just not tried to bake their choice into the footage, shot at 25fps and then allow the editor to make any necessary adjustments with the footage in post, but, they haven't. 

I have been unable to promote the motion adapter on any of the footage to adjust the native timewarp being applied to each shot.

I am also unable to alter clips frame rates from 25 fps to 5 fps from within playback rates in the source settings. Whenever I have attempted to transcode the linked 5fps footage (keeping at source rate for FPS) I recieve the error NEMFileWriter has detected upstream pipestall'. 

Is there any way for AMC to ingest this 5fps footage and for it to be workable in a 25 fps project?

An alternative might be to download Black Magic Resolve and use that. Start a new 25 fps project by importing a clip at 25 fps. Then import each of the other clips. Create a new timeline from the 5 fps clip and then use that to deliver a 25 fps export. This may or may not work as expected. If it does work, import the 25 fps clips back into MC.

I can't guarentee that this will work but it's worth a shot.