I am doing a few changes including legalizing the basement suite and one place I'm struggling to find a good solution is on adding a washer+dryer on the main floor.

In terms of legitimate numbers, besides the construction cost above, remember that the majority of these homes are very old and adding rooms can be tedious, stressful, and might make you want to pull your hair out!

I have 8 washers and dryers in my buildings, I get about $400 per month in quarters.

If they want a washer and dryer, I'll provide one for an extra $50 per month. 

Hiring Guido to drag them out by their hair?  

No refrigerators, stoves or washers / dryers in those because they get damaged and I don't want to be responsible for replacing them.  

I don't think they are particularly unreasonable for a careful landlord, but I think the quality of tenants in the area might not be so great to begin with and including these details upfront makes me come across as a tough landlord:  Application: Background check ($25) Past landlord, employer, and personal referencesLease Points: Initial lease term is 8 monthsMonthly rent of $865 due on the 1st of each monthRefundable Security Deposit of $865Pet Fee (if applicable) of $200 upfront and additional $25 per monthOptional FrontPoint security system for $100 upfront and additional $50 per monthTenant pays for water, gas, and electricityRefrigerator and range oven includedWasher, dryer, dishwasher, and microwave not includedNo smokingAbsolutely no illicit drugs or other illegal activityTenant responsible for damages beyond ordinary wear and tearTenant required to purchase renter’s insurance before move-inNo assigning or subletting without landlord’s permission* The above list is intended only for purposes of convenience and is in no way incorporated into or comprehensive of the Lease Agreement, nor is it binding.

Not only that, my hair and and clothes and all of my things smelled like smoke.

I'm ready to pull my hair out because its been so much hand holding and nagging to get people to follow through. 

My boyfriend thinks that it would be ok to have the washer and dryer in the downstairs unit for both units to share.