Some of these are wrong.

- You can go from TN to EB3; it just gets hairy for the period of time that your AOS is being evaluated. I was going through the process when my H1-B got approved and switched to that. There's a 60 day wait period after you last enter on TN, and you cannot leave the country when the AOS gets filed until you get your EAD and AP or GC, whichever comes first.

- Green card will not take 8 years unless you were born in India, China, or the Philippines. EB-3 priority date for rest of world is March 2016, and it takes longer than 3 months to get PERM approved, so by the time it gets approved it would be current. After that, it takes about 6-9 months to get the AOS approved (and you usually get your EAD/AP a little earlier).