Could you connect a Mac mini directly to a Surface with no third-party display, or would that be a bad idea?
I suppose I might go the complete opposite route and buy a MBP to occasionally run Windows, but people seem to be really mixed on the latest MBPs.
There are several ways to go about using the Surface as the "monitor" for a MacMini. The simplest and most tested is to use some form Remote Desktop. You use remote access to connect to, view, and control the MacMini from your Surface. I used to do this (and still do in various forms) with an iPad instead of a Surface. This method has highish latency (especially over WiFi) in the display and can be rather frustrating if you want to do anything quickly.
The low latency solution would be find a way to get USB DisplayLink working, and have the MacMini output Video directly to the Surface. Something like
Splashtop Xdisplay. I have never investigated doing USB video into a Surface or other Windows10 based system. I'm sure there is a method, but it likely won't be a main-stream plug-and-play product. And will require some level of technical wrangling.
Possibly the better solution is to just plug the MacMini into your existing TV (if you have one) and use a Wireless Mouse and Keyboard. Any LogicTechs one will do. The
K750 for Mac for example, or even just the just the
K750 for Windows will work, and work for both your Surface and the Mini.