Definitely need to find out about RFE.
there is no "peril" about getting border TN with I-129 pending. This used to be common practice when TN was 1-yr duration: one would submit I-129 to remain in status when inconvenient to go to border, allowing one to continue working, and then head up to border at a convenient time and enter on new TN (the TNer would even ask as he entered if the I-129 had been recently approved., and enter on it). Only caveat is to make sure you cancel the I-129 as soon as you get the TN, other wise if the I-129 is denied, it becomes last action, and you lose status, have to go to border, an now you would have that I-129 failure over your head.