2015 Equinox 2.4L Multiple OBD2 Codes: P0016, P0017, P0090, P0335, P228D - What Does It Mean?

Hello everyone, I'm looking for some expert insight on how to diagnose and resolve multiple OBD2 trouble codes on my 2015 Equinox with a 2.4L engine. After installing a completely rebuilt 2.4L flex fuel engine, I'm now seeing several persistent fault codes: P0016, P0017, P0090, P0336 (corrected from original P0335), and P228D. I've already replaced both camshaft position sensors (Bank A and Bank B), the crankshaft position sensor along with its wiring harness connector. I also replaced the fuel high-pressure regulator with a unit that includes the built-in pressure sensor, as well as the low-pressure fuel sensor. The engine was completely disassembled during my rebuild, and I've thoroughly inspected the timing components. I'm now wondering — when people refer to 'tone rings,' what exactly are they talking about? Are they referring to the reluctor ring on the crankshaft itself? That appears to be the only remaining component I haven't addressed. This is the last possible fix I can afford for my wife's vehicle, and I've already spent over $5,000 on repairs. I'm no longer able to afford a professional repair shop visit. Any accurate technical guidance or clarification would be extremely helpful. Thank you in advance for your time and expertise! P.S. All codes are present after the engine rebuild and have not cleared post-replacement.