Over the years we now have electrician, HVAC, plumber, roofer, drywaller, and a general maintenance guy who takes care of stuff not requiring a license. 

You should upgrade this. 110VAC is not normal for a dryer.Just have an electrician add a breaker and run a new line for the dryer with the appropriate outlet.Consider this as a necessary investment/upgrade to your property.

I’ve used the same subcontractors for years; carpenters, electrician, plumber, roofer.

The issue instead is with any labor or skills providers (GCs, laborers, plumbers, electricians, roofers, landscapers - the list goes on). 

Once you have the walls open but before the electrician starts, it might be worth getting an HVAC tech out there to give you quotes for all of your options, including keeping the old boiler. 

I would also have an electrician look for knob and tube and have someone look for asbestos.

.- Plumber- Electrician- Termite Inspector- Surveyor- Insurance (for investment properties)Thank you in advance for any suggestions!

I've had luck with this locally with small operations, like a painter/handygal/former electrician I work with because she was referred to me by another investor. 

Its not rocket science to string wire and electricians don't care to do it all that much.

Our PM company stated that they didn't have an electrician that worked in our area and asked if I could recommend one to her.