Get a good tub from a plumbing supply house and have it installed properly and it will last forever

And real estate demand often outstrips supply.  

This is not efficient, but when I was in the field consistently it didn’t take any time to shoot an address back to my office to research.

I've used Alex Bowen from Jacobs Walker Rice and Barry, the do a lot of commercial and residential real estate work, more popular East of the River but have a newer office down near the center as well. 

If each unit already has it's own shut-off valve then the supply lines should be seperate and you can probably install these.

The 2019 1st Quarter numbers are out for Boston, Chelsea, Revere and Winthrop (Suffolk County).The average price is up by 7.8% vs Q1 2018 and there are slightly more homes on the market (+0.6%).With only 1.4 months of supply, Suffolk County is still an extreme seller's market. 

If not I've used Legal Ease in South Portland to draft my notices, they mail them directly to the York County Sheriff's Office for service so you'll be able to do this all over the phone. 

Try calling a local building supply store.

It supplies 5 units plus the laundry room, hallways etc etc & it averages $300/month but the rents more than compensate & the tenants all pay their own electric.

Most offices are closed and ditto for weekend.