Roof looks great with your brick! I'd follow suit with the windows and get windows with no grids that have bronze frames. (picture below just for frame color reference). For your door I think you could save your door if you're able to replace the ornamental glass insert with a simple one and paint it a bold color that compliments your brick. Otherwise a new mildly contemporary door with cutouts. Definitely remove the teal planters as their tone does not go with your brick. Some simple landscaping with perennials and shrubs underneath the windows would be very pretty. Where is the street in relation to the front of the house?

Pick out colors or whites like you want. Paint on poster board, or buy the peel and stick color patches and put on poster board. Leave a white border all the way around the poster board, so it doesnt clash with the color you have now. Since you want the whole house the same color, then pick a color that goes in your kitchen with your cabinets etc first. Then try it in the rest of the house. The color in there now, does not go with your cabinets. It has way too much yellow in it. I would look for colors that have no yellow hues.

I don't, but if you click on the link that says "More Info" below the photo, you'll see which pro posted it on Houzz. You could then message them to ask whether they still have the color/brand on file. I would bet money that the Benjamin Moore store could find you a sage green in their Historic Color palette that is very similar.

Yes a runner would be safer on the stairs. That raised edge (if I am seeing right) is a terrible tripping situation. My good friend had that and it was really bad. Hope you can get that done.