I think the only issue with transfering the Grom EFI to any of these clone enignes is ggoing to be the CPS (Crankshaft Position Sensor).
A company by the name of Ooracing does certain pit bike swaps on Groms, including the Japanese made 190cc 4 valve Daytona engine, and they do carb conversions with all of them.
I am not saying it is impossible, but likely the amount of time and effort to put into that may not be worth it.
I think the best compromise would be to use as much Grom hardware as you can - throttle body, intake, injector, - sort out a fuel pump, regulator, and install a fitting to the tank for a return. Then run a Microsquirt. Assuming you get a good deal on some second hand grom parts, this route would still end up costing around $600-700
Alternate option would be a full Ecotrons kit, which runs $600, and is actually already well tuned for 125-150cc engines. It comes with everything you need to setup and run EFI.
http://www.ecotrons.com/products/sma...injection_kit/
The third option is basically a chinese made knock-off of sorts of a Megasquirt that uses similar components to the Ecotrons kit. Is this going to be the best route to go? Depends on your budget. There are a few of us Hawk owners that have been eyeballing this kit for some time, but nobody has pulled the trigger to give it a try. Link:
https://www.aliexpress.com/item/micr...c5fdeecf81cf3c
I do know that one Vader owner has installed the earlier version of this (it has gone through some updates since he bought his) and was having a couple of issues with it, but while he was sorting it out the updates kind of stopped.
The other option is to spend the time to get your carb dialed in really well. The difference in fuel economy, if any, won't really be worth the cost of the first two options or attempting the Grom setup unless you plan on riding your bike for tens of thousands of miles.