Tom,
Firstly, thanks for sharing!
Looks like you have an excellent MOC in the works here. Really liking the general layout and you have captured a very realistic exterior. The use of plates in addition to bricks for the exterior wall, and the pattern it brings makes a great look. Liking the imperfections in the side wall, keep these going I say.
Agreed that the solid doors will look better. All you need is a Mna and Fir scribble.
Regarding some of the issues, for me it would be easier to try find solutions in the brick rather than on MLCAD (you must have patience) as I usually try multiple things and often what I think would look best at first ends up not as good as something else.
In general I think the white v brown wall contrast is a bit stark but for sure some old style pubs would have this décor with paintings or odd things hanging on the wall. I think the white looks great for the toilets though as these should be looking bleak right. Interested in seeing what the toilet fittings you mention are and whether they could be relocated or made slightly different to enable a different wall colour. I’m thinking you may have toilet paper holders or something but who knows!
A basement would open up a lot of potential space to add detail and would probably simplify all the colour problems with the interior however being forced to work with the tight space you have here will make a fine MOC if you solve the various issues as it will surely have more character with the nooks and crannies.
If you can post a picture of the toilet area that would be great.
I think it’s a bad idea to have entirely studless footpaths or floors. I always add the odd 1x1 plate in the floor colour which can be used for furniture or figures. It can add a good imperfect effect (IMO) in any case (especially on footpaths).
Best think in advance where you want to place some figures, eg around the bar and have those with the odd stud.
I have some spare LED battery packs. Happy to give you one or more if you think they’d be useful. They take a couple of AA batteries. Personally the wire is too thick and difficult to accommodate the 20 or so light bulbs in a space-restricted MOC like this but if you intend on larger MOCs they could be useful. I used them
here (about 17 of the LEDs are hidden in a riser). My recommendation would be to buy micro LEDs and have a complete circuit and power source on each floor (assuming this is modular). One option I am looking into is using cheap solar powered LEDs for this purpose.