Again, why are y’all discussing this? How is it truly responsive to the debate posted by the OP? Seems to have wandered quite far afield, and I’m confused. 
This is typically covered in the “Allowable Costs” compliance requirements that define the characteristics that a Cost Allocation Plan must meet. Indirect costs such as those for accounting, G&A, etc. are described there and those specific plans are also included when evaluating whether a grantee is in compliance. OMB Circular A-133 covers these items.
What I need to review is whether we every forbid a common indirect pool in a situation like this. Closest we have in my world was when restrictions were placed on funds for fetal stem cell research. But I steer clear of most science involving alive (or recently alive) stuff and didn’t pay much attention other than noting that there was much hoop-jumping.
A particular federal grant may have specific restrictions that exceed the general compliance requirements of OMB 133. The restrictions there are meant to be general so they can be applied to the wide variety of fed grants. In any event, in general co-mingling of fed funds outside the purpose of the grant would be a no no, which you’ve correctly identified.
The issue in the OP is the state not wanting to give money to the church for any reason whatsoever.
The argument is the playground is a secular thing despite being owned by the church so they should get money same as any other playground eligible to receive state money.
So the question arises if it is all one account the state dropping money in for a playground really is the same as supporting religion because now the church can use the $100 it didn’t have to spend on the playground to evangelize. Poof…state sponsored religion.
The argument then hinges on whether the church having two separate accounting books, one for religious activity and one for secular activities would fix anything.
Make sense?
No. Of course not. Thay is putting form over function in the interpretation of constitutional principles. Where else do we engage in this sort of silliness?
Bumping this thread as it is SCOTUS watch time. June is winding down and that means the end of the current term for the court. There are only six cases left from the current term that have not yet had an outcome released. Opinion on Trinity Lutheran Church of Columbia, Inc. v Comer (and the other remaining cases) will likely come as soon as Monday June 26 with the court scheduled for proceedings at 10am EDT.
Caveat: in theory the Justices could rescheduled any of these cases for further hearings, Dismiss as Improvidently Granted, or Remand to a lower court among other possibilities that would not result in an opinion on the merits. Three of the remaining six cases were heard before Justice Gorsuch joined the court so a tie vote is considered more likely on those with a higher possibility of a rehearing in the fall. Gorsuch was already on the court when Trinity was heard on April 19.
Three of the remaining cases were heard in April. And justices tend to spread the work around, writing one opinion each per month - two at most generally.
Speculation over on SCOTUSblog is that Chief Justice Roberts has not yet written an April opinion. If he is in the majority then he gets to choose who will write the majority opinion and it is normal for the Chief Justice to pick the bigger cases. If Trinity is a Roberts opinion then the church is the likely victor given discussion about how the justices seemed to line up during oral arguments.
If not Roberts then Kennedy, Breyer, and Kagan also have not written an April opinion. (Alito and Ginsburg have two April opinions each so it is highly unlikely they are writing the majority opinion). During oral arguments only Ginsburg and Sotomayor seemed squarely on the state’s side. So its really not looking good for the state in Trinity. Best the state might could hope for is a Breyer opinion though even he seemed troubled by the state’s arguments.
Opinion here: https://www.supremecourt.gov/opinions/16pdf/15-577_khlp.pdf
(Looks like Gorsuch will be to the right of even Alito.)
Do you mean with respect to religious issues, or other issues too?
I hope he’s open to same-sex marriage, because I may wish to marry him.
No, you can be pretty sure he thinks gay people are not entitled to legal protections.
Based on his opinions today, all issues. For example, he would also have agreed with Trump’s obviously bogus national security justification for the travel ban.
On the contrary, I’m sure he thinks people are entitled to any protections the legislature mandates. He figures out the law by reading its words. Opposition to this approach has taken the short cut of suggesting or directly saying that this translates to hostility towards gay people. It is not. It’s fidelity to the proper way to interpret law.
If Congress added “sexual orientation” to a non-discrimination law, I guarantee to he’d be its vigorous advocate.
7-2. I didn’t think Breyer would side with Trinity.
That’s a lot of words to agree with me that he wouldn’t require states to recognize gay marriage.
[omitted pissy aside]
With Roberts writing the majority opinion. May be a blow to state level Blaine Amendments nationwide.
I have begun charging my best quartz crystals in my home pyramid with the aim of harmonizing Justice Kennedy’s mind with the word “retirement.”
Stay tuned (ha!) for further results.
That would be a sad day for the Court. The Court NEEDS centrist jurists to act as the fulcrum on which the extremes can try to create balance. It’s one of the worst things about the Court for the last several years that he’s been the ONLY centrist left on the bench.
Having said that, I expect he’ll retire. Those who will tell him he should stay would be telling him he has to stay for at least four more terms, and that’s asking a lot.
Maybe he’ll go back to my alma mater and teach some more Con Law. That would be nice. 
I thought I recalled that Breyer was a bit hostile to the state during argument. For whatever reason, I predicted 7-2 at the time.
It IS interesting reading the opinions and seeing exactly what everyone was thinking about the future of similar challenges. Breyer’s opinion says, “This case is a no. No need to talk about future nos.” In contrast the opinions of Gorsuch and Thomas say “This case is a no. And why are you bringing up potential yeses?” 
I thought it a bit flip that Breyer would downplay the precedential nature of the outcome.
I would bet Kennedy doesn’t retire just yet. I expect he’ll serve one more term, then retire. At first I was on board the retirement rumors, but in hearing that he hired his four clerks, it would be too dickish to do that while planning to retire.