Just for the heck of it, here are the numbers on what each of the following schools' athletic depts spent for the year and what they specifically accounted as spending on football, for the 2015-16 school/financial year (the latest year for which data is available):
U of Minn - $99.5M / $25.5M
ND St - $25.3M / $4.6M
Mankato St - $11.3 / $1.3M
St Thomas - $4.5M / $1.1M
These numbers come from the US Dept of Education, which tracks all this stuff for Title IX purposes. And they may not all be exactly accounted for the same, but just to give a general idea.
So you can see how much of an uphill battle it would be for schools like Mankato and St Thomas. Especially because, in both cases, they have hockey. Now Mankato's hockey program is already fully funded, as far as I know, and wouldn't be at risk. That's the major revenue sport in their athletic dept .... the same as Duluth. But it is a significant expense, when you then add in the costs of trying to go DI in the other sports, let alone football.
St Thomas on the other hand doesn't give any athletic scholarships. They'd have to upgrade every sport, including hockey, to the DI minimums of athletic scholarships, spending, etc. They might have to drop hockey to do it.
And in both cases, I wouldn't be surprised if they dropped football or at best brought football up as non-scholarship (there are no minimum scholarship requirements in FCS football)