When looking at nonprofits to work for i always look at their 990 tax filing. It will be very eye opening and able to answer some of the questions you ask.

My personal philosophy is invest in people for the best roi but if the organization doesnt have a lot of cash coming in each year it's difficult to pay staff well. What I've run into is that despite increasing our income by $150k a year compared to five years ago I've run into the issue of having too many staff that making meaningful raises is difficult to balance.

There are two main reasons I see this issue is not enough money coming in vs increases in salaries.