If your fuel injection / combustion is done in a way that carries the velocity, like an ejector jet, then you could get some airflow going at zero forward speed. The idea of regeneration from the thrust augmenter seems like a good one. A loop like that should raise the overall system pressure. Raising the pressure will raise the thermodynamic efficiency. NACA ARR No. L4F26 has lots of information on the WWII studies of ductwork which would be applicable. Just inside the inlet the regenerator air should be made to work like those "bladeless" fans that don't chop the air, which should allow the air in the engine to accelerate until drag effects prevent further acceleration. If a fuel like propane is used, it could conceivably be used to cool the outer inlet, further increasing efficiency.
Lets say all these tricks are used and it still wont give you the thrust you are looking for. Virtually the same design could be used with a motorjet, where the regenerator air or the inlet air is blown by a separate motor/fan. Motorjets work and large aircraft have been built and flown with them. Point being after you build your regenerator ramjet, you can always boost its low speed performance if it doesn't meet your needs.