vent/waste line for moving toilet question

I am researching if I can move a toilet or not.

I am not going to cut a joist to do this.

1. There is already a "box around" ducting in the laundry room under the bath. Is there any reason why I can't widen the box and run a 3" waste pipe though it?

2. The other obsticle is how to vent it. Its quite a ways to the 3" inch vent. I've seen lots of drawings of vents but none of them show my situation.
2a. Option a. There is a 2" vent that vents 3 sinks and the toilet next to to the laundry room in the basement. Maybe the washer too. Would a second toilet be too much?

2b. The wall comes be before the 90 degree fitting that takes the waste to the "box". There would be a second 90 inside the box that would bring it to the main waster/vent line that. The vent would have to be 2" because of plumming in the wall, but I suppose I could move it. There would also be two 2" lines running within inches of each other, would that affect the wall strength?

................90 to vent
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Toilet=====_=====90
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............................90=========||main