help cutting in a temporary shower

I am putting in a temporary shower and will have to put in a pump up system and have two questions I need help with.

Will the pump up sink units handle a shower unit? Based on volume it looks like they will but just want to make sure.

I was going to run a temporary cut in to a drain line in a lav. thru an a ajoining wall. Can I cut into the the 1 1/4 drain above the floor with some sort of y so I can remove it later.

Thanks in advance for any advice Tom

As I understand it, a shower requires a 2" drain line. You might have a problem. My unprofessional opinion.