100amp to 200amp Service Upgrade
You will need to use RMC, not EMT, for the service mast
The first order of business is that your utility's overhead service guide requires the use of RMC/GRC for service masts.  You are correct with using 2&quot; for mast sizing, though; inside the mast, I'd run 3 4/0 Al XHHW-2 individual conductors in order to keep pulling reasonable and comply with Code limitations on what can be used in a conduit to begin with.
I like the thinking with the conduit to the interior panel, but it sadly won't quite work due to stud boring limits
Sadly, your plan with running oversized conduit from the meter-main to the panel won't work either.  However, this is not because it's electrically wrong at all, but because of mechanical issues.  IRC R602.6 point 2 limits holes in studs to 40% of the stud width, or 60% if the bored stud is sistered or fitted with an approved stud shoe to reinforce the area around the hole.  However, this limits a 2x4 nominal stud (3.5&quot; wide) to a 2.1&quot; diameter hole, even if a stud-shoe is provided, while 2&quot; PVC or GRC has an outside diameter of 2.375&quot; and 2&quot; EMT has an outside diameter of 2.2&quot;.
So, you're better off exiting the lower rear of the meter-main directly into the basement with your 1-1-1-3 SER cable and then running the SE cable up to the subpanel via whatever route works.  That means you'll have to replace the SE cable with a 4/0-4/0-4/0-2/0 SER and overbore the studs and joists from 1.25&quot; (achievable without stud shoes) to 1.75&quot; (which requires stud shoes) if you want to upgrade the interior panel to 200A down the line, though.