Boot camp allows you to run windows, it doesn't depend on Apple drivers. Windows 10 has native support for TB3, it's not Apple proprietary. Folks are already using eGPU enclosures over TB2 in bootcamp on older macbooks.
1.
in a sufficiently great or important way as to be worthy of attention.
"energy bills have increased significantly this year"
synonyms: notably, remarkably, outstandingly, importantly, crucially, materially, appreciably;
No it isn't. The CPU in the Stealth is a 15w TDP part, that used in the new Touchbar MBP is a 28w TDP part. That means that while they may benchmark similarly, the MBP will be able to sustain performance for a much longer time without throttling. The Iris GPU is also a significant upgrade in the MBP.