The renovation process may involve updating the interior and exterior of the home, replacing outdated fixtures and appliances, improving insulation and energy efficiency, as well as meeting safety and code requirements.

Choosing the most expensive insulation because it's the most energy efficient, should allow you to reduce and/or eliminate costs in other areas.4 - Energy efficiency isn't made up of added costs.5 - Energy efficiency is the product of reducing energy needs, not supplying added energy.6 - Cost effectiveness is a product of maximum use of materials, as in little or no waste.All of the above should be obvious, in parts. 

They can buy and install windows/insulation/cabinets/etc for less than you can buy them for....

Insulation?

Are there ways to improving the sound through foam insulation in existing walls?

It makes it very easy to find customers even with bad support.I am leaning towards going with the click plank option as I was told, that when it clicks together it adds another substrate or "floor" basically and that with the attached underlayment does a pretty good job of reducing noise.I looked at adding gypsum concrete (gypcrete), self leveling cementitious subfloors, wool insulation under the plywood, and another type of cement type floor, but they all have their pros and cons and doesn't seem to be worth the extra money in the end. 

If your shell is back to the studs, just getting the rough in phase; insulation mechanical, duct work, electrical, plumbing passed inspection, with the holding costs that will put you over 100k.  

Even the correct insulation matters. 

with an 1880s wood building (age of many 2 flat buildings) it’s not if you have rotted wood but where. for me it was a constant battle caulking/replacing windows spraying insulation to keep cold air out and conducting yearly termite inspections. you might still have some of these issues with brick buildings but you have more time (fix it this year as a opposed to right now) @Mark Ainley curious if you have any other anecdotal reasons why brick is better than wood- i know i’ve heard this come up on the podcast numerous times

Personally I have lived inside without heat or plumbing for months. floorings plaint insulations those were things I bought weekly as I could afford them.