Ah, I got ya. When you said, "the PVC that goes left head about 15' - 20' to the future bathroom" I thought the future bathroom was on the first floor. Now I see you mean that is the future vent for the basement bathroom (which is why I was curious about the 2", which as you know wouldn't work for a WC)
If that is all vent piping, then it looks good
Figure 2 that you attached depicts a vent stack and is not something I would refer to.
If I am understanding your plan, it sounds like the future bathroom will work as you describe. Between the lav vent and the sump vent you may not need any more vents if your jurisdiction allows horizontal wet venting.
Sorry for confusing the matter.
Tim
If that is all vent piping, then it looks good

Figure 2 that you attached depicts a vent stack and is not something I would refer to.
If I am understanding your plan, it sounds like the future bathroom will work as you describe. Between the lav vent and the sump vent you may not need any more vents if your jurisdiction allows horizontal wet venting.
Sorry for confusing the matter.
Tim





























