Agreed, nice buildings - nice to see wonky roof lines. There's a few true 15mm MDF buildings around now, but to me they just look much too square and neat. Which would be fine if it was a representation of some Inigo Jones architectural masterpiece, but not for most buildings used by the hoipolloi. I know they are printed and are therefore scalable, what height to the roof apex are they? And where did you get them from? (I have neither the space or inclination to have a 3D printer, so purchasing printed models would work for me). Have a look at the Hovels buildings too 75mm to roof apex, so true 15mm but with a reduced footprint (there's a few reviews of them over on my blog, which I'm guessing you have used for your coat colour references).
On the subject of historical hat colours for Fred, from surviving examples pretty much shades of brown all the way, woollen Monmouth and Montero caps were more brightly coloured. Royalist Oxford issue included matching red or blue Monteros. Surviving Monmouth cap is a dark brown, but similar style contemporaneous Dutch whaling fleet 'beanies' are multi coloured, some are striped.
Your RoF look good, I think those with muted hats look much better, but I understand your artistic reasoning. Can't help but think they'd benefit from some individual halberdiers barking orders at the musketeers (as in Streeter's Plan). Surely Warlord have missed a trick there - there's quite a few things missing from the range that I'm surprised they haven't filled.
I noticed that your reference material is Young and the Osprey. Young has some good material but Is quite dated now, the Osprey is dire.