Basement Bathroom addition

I've been reading through the forums and picked up some invaluable information but was hoping for some specific information. I've attached a copy of my proposed layout. The ejector pump is required because my main drain exits the basement wall about 3 " from the floor. There will also be a sink to the left of the toilet and a kitchen sink just south of this entire diagram. Both of these appliances will share a vent with all the kitchen fixtures but will drain into the main.

I have a few questions about making a vent. All the other fixtures in the house are on the main level (none on the second level). Assuming that there is no vent dedicated to the basement, will I have to run a line up to the attic (or at minimum 6" above the flood line of all upstairs fixtures)? Is there any way to vent into any other lines? I've attached some photos of the existing plumbing work.

Lastly, am I correct to assume that I need either a combo or a wye and a 1/8 on its back to shoot the 2" vertical vents in my diagram? sanitee will not work?

Thanks for any help that can be offered!

The sewage basin and the fixtures traps must be vented, either on a dedicated vent or tied in 42" above the main floor. You cannot tie into a vent below the flood rim of any of the fixtures it serves.

A sanitary tee is for transitioning a horizontal drain to a vertical drain, it should never be installed laying on it's back.

I would keep the 3" line straight from the water closet into the basin. The sink drain will be in the wall with a 1-1/2" vent going up and a 2" drain going to a wye into the main line. This vents the water closet through the sink's vent so that the WC will not need it's own vent. Tie the shower in with another wye closer to the basin. The shower's drain should be 2" but it's vent going up into the wall only need be 1-1/2".