I think carb cleaner is safer, but either is safe(ish).
If you don't have the clips on the injectors, then that might be it.
Also, fyi, I didn't have an eml before I did the intake...did that for cooling system hard pipes. I got the eml because in wrapping things up, I forgot to plug back in a few things...Round plug (thought that was icv, not TB...but guess you're right)...the oil pressure sensor on ofh...and also the temp sensor...and I think I forgot one plug back by the driver...forget which one it was.
Get an inspection mirror and 100 lumen flashlight (or thereabouts) if you don't have those things...and start by just looking. It's hard to see the vac hoses behind the intake mani, but getting off the cabin air filter housing is very easy...ditto air box.
I can't see that that one broken stud is leading to a large enough leak that it would trigger eml. I think some electronic thing is unplugged...
Vanos solenoid maybe? Remember, you unplugged a lot of crap to remove that thing.
You could carefully spritz short blasts of carb cleaner by the likely sources of leaks. Your wife doesn't have to keep it running. If the engine spurts up where you spray, there's your leak...if your issue is a leak, that is.
I think you're going to find an unplugged connector. Sorry!