Good day Looper,
Sure that should work fine. Windows OS supports MST, so no problems there.
What you need to check is how many screens you can output thru the DP out on that Dell XPS13. Most notebooks do not have a DP1.2 output and when they do they are often limited to output a maximum of 2 screens thru the DP output (plus the Notebook screen makes 3). We did not test with an XPS13, but somone at Dell should be able to get you that info if it is not in the manual.