Curtain colour (for gimp - there are numerous methods this is just the easiest) - duplicate the curtain layer and place it just above curtains and rename it 'curtain hue' ; make sure that any shadowing is removed on this new layer, and anything else you don't want to change colour not included ; select all (alpha to selection) on 'curtain hue' layer and fill selection with your desired final hue ; change layer type to 'hue' ; adjust brightness/contrast/saturation of underlying curtain layer as required. If you want me to do this just post up your curtains as .pngs but make sure to remove all shadowing first.

Entrances much better. I can make you a nice decorative door if you like. It needs to have blue and gold and white and black in it and be very baroque.

Lamps - careful here. Have a look at streetlamps or modern map elements for these, and we will change their colour to gold (which usually also involves changing the colour CURVE to make that metallic glint). Fantasy-type lamps will not look good here I suspect.

Basement plan - I think should be heavily revised to remove all those tiny crappy rooms (which are un-playable with) and make it more interesting overall. Very much a fan of idea of linking up the two basement areas (secret passage!) that has a side route leading into the city sewers and a rat-infested ancient dungeon.

Basement - I disagree with anstett the maps are already brown enough so we should use stone for the basement (greyish-blue) not dirt, for aesthetic reasons. This part can have fantasy-type lamps with goldy-orange flames.