Is it in accordance with TRADOC Regulation 350-6 that 35Ms, post-completion of MOS training, are still considered IET status while at DLI?

You are still in IET status until you report to your first duty station.

Depends on what you're asking about. As a Mike, I think you have to complete DLI to actually be MOSQ. Otherwise you have to complete a different 35 specialty

You are IET until you compete ALL of your training and get orders assigning you to a duty station. I have known people to fail their language and receive an ELS. So yes... You are IET