You could test this by replacing a steam application with the demo from here, but I somewhat doubt that SRPT goes as far as registering virtual keyboards/mice. A tool that I'm currently developing allows to write input adapters to map keyboards/mice to a virtual gamepad.
One of the recent Steamworks SDK versions added a few functions to fetch remote players’ inputs separately, but still they do not simulate Raw Input.
I’ve been working on an extension that automatically wraps majority of Steamworks SDK functions so that calling something esoteric like this doesn’t require messing with C++ - send me an email (and include your GM / Steamworks SDK version numbers) and I’ll get you a copy of it so far.