RE: Ignition power from receiver?
The proposed system is not a regulator, but a switch with plenty built-in filters. Might work OK since it is designed not to let power ripples and RFI (Radio Frequency Interference) past its terminals.
Being old fashioned, and scarred by experience, "might" just does not make me happy with the idea, unless there is a high power RFI test done on it, which I doubt.