Nice diagram. What software did you use?
I'll let the pros opine about venting 2" into 1.5" (my guess is that it will work, though. I wonder if you can 'supplement' it with a studor vent.)
As far as the drains go, if you're going to be doing the demo yrself and want to minimize the work, I'd run the sink drain above ground and enter the basin via a wye in the toilet's vent. The 'wet section' of the vent will only be a few inches. I did that and my inspector passed it.
Also, I'd aim the shower's ptrap 'southwest' instead of going due west and then 45ing it. This will eliminate one bend and allow you to make the sweep into the main line double wye a little gentler. I'm just picking nits here, though.
If yr planning to do the demo and rough work yrself, drop me a private line. I have oodles of advice on it - all to be taken with a grain of salt, of course, but I can give you a good diyer's perspective on the level of difficulty, lessons learned, and the costs/benefits vis-a-vis having it professionally done.
Also, one last thing: Are you married to your flotec pump? If you search the forum here, you'll find a lot of negative opinions about them. A better choice seems to be Zoeller. I read those postings too late after I had already committed to my flotec. I don't have any problems after 6 months, but am waiting with bated breath...
For fittings, use wyes and 45s instead of sanitary tees wherever possible.
Purple Prime all joints b4 cementing.
I'd cut the vent and discharge lines above the ejector pump and reconnect them with hubless metal-sleeve couplers. This'll make it easy to get into the thing if you have to do maintenance.
Get a good check valve. Solid pvc or iron, full flowthrough. (not the wimpy rubber one that would come in a flotec simplex kit). Your diag doesn't show where the discharge runs and how the check and gate valve are run.