So after some digging, seems like this vibration is common with cheap replacement axles. I was able to pinpoint the vibration, most prevalently in 2nd-3rd-4th gears 35-55mph, with a bit on the highway around 75mph.
OEM axles were about $450, so that was a non starter. I ended up ordering a pair of NAPA Max Drive axles (remans) built for NAPA by Cardone.
These were about $120 plus core vs the $45 I paid for the Surtrack axles.
Went about swapping them in today, once the Surtracks were out, I laid them side by side with the ild OEM piece, the passenger Surtrack shaft measures about 8-9mm smaller in diameter than oem, the drivers about 4-5mm smaller...I'd hazard to guess the smaller shafts probably are more susceptible to vibration along with likely other shortcomings in quality. In the 250 miles they were in the car, there was already noticeably play in the joints...they will be returned...
OEM axles on bottom:
TLDR: New cheapo axles vibrate a lot, NAPA reman. axles fixed the vibration....the rock also boned me by sending the wrong axles seals and I left the originals in place. Axle swap #1 resulted in no leaks, i don't believe I'm that lucky on axle swap #2. I will have to see which is weeping and order a Toyota seal.