Adjustment of Status - I-485

I'm a Canadian adjusting status through marriage to a US citizen from a TN visa. I'm currently working for a very large company (I guarantee you've heard of it) and have gotten my second RFIE 6 months after filing.

Timeline is:

9/11/2017: Submitted I-485, I-130, I-131, I-765 concurrently
9/13/2017: Everything was received by USCIS.
Early October: Did biometrics.
10/10/2017: 1st RFIE sent out (evidence that my wife can support me - she's not working so we used my income to show evidence of support).
11/03/2017: Response to 1st RFIE received by USCIS.
Waiting
Waiting
1/4/2017: Raised SR #1 about EAD online. No response ever received.
1/17/2017: Raised SR #2 about EAD online.
2/12/2017: Booked InfoPass appointment. Told just to keep waiting, nothing they could do.
2/12/2017: Got response to SR #2 about EAD: "your case should have a decision or other action shortly".
2/20/2017: Raised SR #3 about AP being out of processing time online.
2/22/2017: Filed complaint with Ombudsman (approx 160 days) about lack of EAD and AP.
3/5/2017: Got notification via status update online about 2nd RFIE (175 days after filing!) on my I-485.

I-131, I-130, and I-765 are all still in the "case was received" status.

Short of contacting the senator (which I'm already starting...) I have no clue what to do...

I'm curious if anyone here has anyone ever had a RFIE sent out 6 months after the original filing date? What I'm puzzled by is why wouldn't they go through the whole packet and send out for whatever info they needed back in October?