Decisions, decisions...

[goodguy]

Id recommend the tamron 24-70 instead of the nikon version, its a better lens.

For the money the Tamron is a good buy and a very valid choice but I wouldnt call it better then the Nikon 24-70mm 2.8G
They are very close and when it comes to value for money then the Tamron might be considered as a better value for money but it is not better or superior to the Nikon.

Its sharper, and has vr.

I am not going to get into an "it is, it isnt" back and forth argument, read Post# 10 written by "Netskimmer" which pretty much say what I read too.
VR is a plus and helpful for sure but far from being a deal breaker.
Value for money ?
Tamron
Which is best ?
Too close for call, I chose Nikon and would choose it again considering the price I got it for, if I would consider getting both new I would lean more toward the Tamron.

 

[LostLensCap]

I think you have a very workable plan. You might pickup a 50mm prime along with your D750 for low light and a normal perspective.