Thunderbolt, Keyboard, SD Reader, and Trackpad stopped working

[hill.evan]

Hey MacRumors community,

I have a late 2013 15’ Macbook Pro Retina. 2.3 Ghz Quad i7, 16gb Ram, 500 SSD and Dual Graphics ( NVIDIA GeForce GT 750M 2048 MB, Intel Iris Pro 1536 MB).

Issue:

• Initially, random shutdowns. Computer would freeze 5-10 seconds, fans would run, and shut off. No message prompt or error screen when I fired it back up.

* Took it to apple (possible first mistake), replaced battery for $300. New power chord $100

• Shutdowns returned after about 2 days. I troubleshooted online and found others with the same issue routing back to Thunderbolt Ethernet Driver. Found instructions on how to disable the driver and hopefully resolve the problem. (instructions here - outluch.wixsite.com/rmbp-crash)
• Before I could execute the instructions, my keyboard and trackpad stopped functioning. I also noticed both thunderbolt ports and SD card reader stopped functioning, and aren’t recognized in system report.
• I can’t get the computer to boot in diagnostics or disk utility to clear the drive. The computer just boots up as normal (this could possibly be due to the keyboard not functioning?). Can’t tell if SNC NVRAM resets are working as I’m trying on both the attached keyboard and an external via USB. No change.
• I did briefly get the troublesome folder with question mark a few days ago. Booted up again and since it’s been running fine.

Question - For someone with knowledge / experience, IYO does this sound like a failing logic board? Another piece I’m not familiar?

Many thanks ahead for the time,

Ev