I've been reading theories online that Chris Pratt will be himself in the real world then get dropped into the world of Mario which is why he sounds exactly the same and has no idea where he is which sounds ridiculous until I read a comment saying that Mario collects Stars therefore he is a.......Star Lord!!!

Putting my tin foil hat on now!

I don't think he'll go from the "real world (as in non-animated)" to the Mushroom Kingdom. He doesn't look at his hands, his body, or anything like that. He is mostly surprised by the world he has entered. I think we'll see a small scene with him and Luigi in a fictionalized cartoon Earth where he's working as a plumber. He doesn't show up at the same time as Luigi, which makes me wonder if he goes in after Luigi or vice versa. I suppose the two could both go in together via whatever pipe as well and end up in different parts. I am wondering about the lore of Princess Peach. Like Mario and Luigi she is human. Do they know her in the real world? It's good that we'll be getting canon straight from the horse's mouth with this one.

I'm on the Chris Pratt team by the way, for the record. The over the top Italian accent is fun and all in the games as a one liner or two, but a whole movie like that would become cheesy and annoying. I'm also curious about Peach.

If they start out in the real world, I would cut out any scenes of him being surprised by his body in the trailer, since it would be an interesting surprise for the audience.

I see your point, but thankfully I don't see any evidence of that happening yet. I personally am not a fan of the real world tethering for many franchises.  Smurfs, Alvin and the Chipmunks, Sonic, etc.  I'm hoping they keep this as far away from Earth circa 2022 as possible.  That place is trash.   

I don't think there will be any live action scenes. The very idea is stupid to me. Illumination doesn't make live action.

Chris Pratt’s Mario Voice - YouTube

Well I don't have any preferences regarding this either way. But that could explain why Charles Martinet isn't the lead role (since there would be live action acting and they want the A-list actors in those scenes), while he is credited in the movie. Perhaps there's a scene with Chris Pratt playing Super Mario, and Martinet does a few lines for the character there.

Actual beginning be like:

The Mercedes Live action Mario film when?

So who’s watching this in the theater day 1?