Looking for feedback on whether to invest in the changes myself or give money back/reduce the price to cover it.  

Explore ways to reduce your personal expenses AND increase your income (side hustles) and save that difference.PM me if you have Q's.

I guess the reducer on top of the top tread is okay then but the current installers did not put one so when I replace I have to be sure they do. 

If so, I think their main concern would be your time and energies going towards something other than the job they hired you for.

It's got curb appeal, and you may be able to reduce your mortgage payments by renting out the rooms you don't occupy, but it's not great from an investment perspective.

Or you can opt to reduce coverage in order to save some money, but that in turn increases your risk.

If it'll reduce vacancy or allow rent increases in the amount $50/Unit, that's $150/Month and it'll repay itself  before the 1st year.  

I'll work extra hours if it means eliminating, or at least drastically reducing, childcare costs. 

That will give you positive cash flow and a reserve that could be easily needed when doing REI/ or be the money to furnish the house, deciding to live there.The difference in putting 25% or 3.5% would help you to accelerate the rebuilt of reserve, and more important will reduce leverage.

It’s so hard to back track and reduce your expenses later on.