In Pennsylvania, does a district have to have documentation somewhere that specifies how they identify kids for RTI versus IEP versus nothing?  Is that something that has to b in the special education plan they send to the PDE every couple of years? I know IDEA says you don't need academic failure, but in the case of 2e kids it's hard to hit whatever magic testing threshold the District is looking for to warrant an IEP because "average" on language processing evaluations is dismissed because WISC Verbal Comprehension Index is over 130 and there is likely some self-compensation going on.

I'm not in Pennsylvania, but a lot of people on this site are, so hopefully they'll jump in.

But from a general standpoint, some (most?) states require school districts to have a written policy on their RTI process, as well as their procedure for determining eligibility.  (Now whether or not school districts actually do this is another issue...)  Have you reached out to your school district to ask for their policies?  If they say they don't have any, you might find something on the state department of education's website about "standards and indicators" for determining eligibility or a state plan.

RTI & MTSS are general education things so no need to tell PDE anything about this in the report that covers sp ed.  The Child Study Team (your school might give it a different name) should have a rubric for identifying students for RTI & MTSS.  You can ask for a copy.

If you suspect autism & issues with pragmatics, you want something like the TOPL to be done.  With a bright child who masks, you want the optional extended assessment to be done or they might say your child is average.  I speak from experience.

Applying for Medicaid for your disabled child and having them cover speech therapy outside of school is also an option in PA.  This is the application if you want to do this:  https://www.dhs.pa.gov/Services/Assistance/Pages/Apply-for-Benefits.aspx

I don't know what going's on other than achievement isn't matching IQ (the kid is doing the work). A comprehensive language processing eval was done which did CELF5, LCT2, LPT3, TAPS4, and articulation.  It looks like only the CELF Formulated Sentences is the one subtest that may look like it addresses pragmatics. The score was in the 98th percentile.

This will be listed in the school district's policy. And yes, they must have a written plan for RTI/MTSS.