Was it hard to move off Retina and reasonable touchpad? I am considering similar route, but these are the two things that keep me on Apple.
I like the touchpad on my X1 Carbon, but I never used a mac long enough to really adapt my workflow to all the touchpad gestures (I think on Linux you'll be happy with general usage/scrolling/etc, but stuff like pinch to zoom is still not widely supported).
Surprisingly, some Tk applications that I use irregularly actually work with HiDPI with Tk 8.6 (as in, they are scaled up with an integer scaling factor, and are sharp).
Multiple displays with different DPIs also work with Wayland (I have one 4k screen and a LoDPI display 90 degrees rotated). Though, there are some bugs with GNOME 2.26 on Wayland with HiDPI displays that are switched off and on again (e.g. some applications such as GNOME Terminal become blurry, they seem to be rendered at lower DPI and scaled up). I have reported some bugs and the gnome-shell/mutter developers are quite responsive.
HiDPI is generally pretty decent although it's slightly annoying that different layers of the graphics stack (Xorg, GTK2, GTK3, etc.) have different mechanisms for tweaking the scaling but with a few evenings of work, I have everything dialed. A small price to pay for years of use to come. The Arch Linux wiki is super helpful for this.
You want to look for windows precision touchpad support. Turns out the problem with windows touchpads was not the hardware, but the crappy drivers touchpad vendors make. Microsoft made their own drivers and if you can get hardware compatible with those you'll have a much nicer experience.
The touchpads are fine too. I regularly bounce between a macbook and a T460, and I don't have any problems operating the latter.
Yoga 900's touchpad is way worse though, so if you really care, always check if you can try it first.