Hear, hear @jfrater this is the best advice you've got!
I posted a query about a two tone boot from Enzo Bonafe via Skoak recently and wanted to follow up with a picture from my first outing with it. The colors are fairly muted for a two tone boot and seems to pair well with flannels, tweeds and even dark denim (balmoral boot and denim, gasp). The green also prompted me to kop a Jade SS merino from @tchoy, which is en route. I'll post a few more combinations over the next few weeks for giggles.
@jfrater, Claghorn is right on the money in describing it as a rule that can easily be broken, depending on the jacket. I might reach for a stitch cap toe with a very city blazer and tie and go to the other extreme of a scotch grain boot if I'm wearing tweed without a tie. Generally speaking, I find myself reaching the most for suede oxfords and shell wingtips (short or long wing bluchers). I do not have any double monks, but I think yours would be a solid choice along with your half brogues and some of the less sleek wingtips.
I also agree with the others on not buying anything else for now. If I were you, I would pay attention to @Cleav 's shoe collection over the next few months and create a wish list for very specific pieces. He has an amazing collection and does a great job pairing them with his fit each day.
The only place I depart from the others are the shoe laces for #26. Those are not my cup of tea, but I think that is the AE Neumok, which is intended to be a casual shoe worn with jeans.
I think at this point in our history the Blucher(Derby)/Oxford distinction is best understood as one of several casual/dressy distinctions which may or may not render a particular pair inappropriate in a particular fit depending entirely on the other elements in the fit. And I think the distinction itself is best understood these days as merely a particular example of the broader principle that (other factors being equal) departures from simplicity are departures from formality, and for that reason the extra leather on the Blucher makes it less formal than the Oxford. I’m not sure much more than that can be said. That individual fits need to be analyzed individually is a pretty foundational principle.
As always there can be conflicting principles. One such principle in the present case is the principle that elements which attract attention solely for their novelty constitute for that reason a departure from formality. It might have been Manton who felt that way about whole cuts; in any event I do. Despite the eliminate of all decoration, the sheer novelty of the things at this point in our history can make them stand out almost as much as spectators, albeit for an entirely different reason.
I expect that if wholecuts become more common they will gradually lose this novelty and in a couple of generations the psychological effect just described will disappear. This is normal, and is just how the classical style evolves.
Don't wear a navy pinstripe for a job interview, unless it's for a senior position in a bank...
Edit: good luck with the interview!!