2nd Floor plumbing plan

This is a plumbing plan for my attic addition and would like your opinion. I have limited space below the floor is the reasoning for using a 45 degree toilet flange. I have about a 25' run before the line goes vertical into the main line under the slab. The city inspector already hinted that I should use a 3†vent, for what reason I am not sure.

The vent san cross, 3"x1.5" is upside down.

The vent for the toilet should be rolled above the flow line.

The lav should be wyed into the line below the wc vent.