Since a lake house is a retreat how about Sherwin Williams paint color by that name? A few years ago, I changed my house from the generic subdivision tan/taupe color to Sherwin Williams Retreat. I couldn't believe how many neighbors and even strangers stopped to tell me how they liked the color. My front yard only has one tree in it but my shed is surrounded by trees so below is a shot of the shed so you can get an idea of what the color looks like amongst the trees. The cool thing about the color is the way it changes slightly depending on the sunshine or cloudiness of the day. Its listed as a green. Sometimes it looks more green, sometimes its more blue. It's a blue/green, a green/blue and even a blue grey or green grey.

So long as you use a ceramic or mineral based paint you should be fine painting the brick. It basically makes the maintanence that comes with painting brick disappear. The house looks a bit dark as is. I would paint, personally. It would help bring this 70s house up to date. Maybe an off white or gray to help it go with the roof. You can also get more creative with trim and shutter color this way.

I'm not a professional so take the ideas for what they're worth. :) Looks like your windows are framed in white? How about painting the window trim white (it might make the windows look larger). Carry the white trim wherever you have the dark blue trim. The light blue siding would look pretty in a light to medium gray (and wouldn't clash with the roof). The door could be painted a pretty pop of color. I'm a big fan of red doors. It doesn't have to be fire engine red. Looks like you have a plant near the door with reddish blooms. Perhaps a wine red door? Hope these ideas get the ball rolling for you. Good luck! I'm experiencing a similar problem with my shutters. Wish I had a photo I'd share with you to get your ideas!

one more vote for your mockup with teal and chartreuse door (and those windows you chose look so much better). I think if you replaced the hedge by the garage to the front door with a small chartreuse leaved tree, grasses or shrub it would complement the door and make it stand out less. (I don’t have photoshop to put these ideas together) and maybe add some chartreuse lawn chairs? I like the garage door painted the same color as the siding but you could also match the color of the stone instead of bright white. here’s some ideas for plants or check with your local nursery: https://www.finegardening.com/article/chartreuse-foliage-makes-a-splash https://davesgarden.com/guides/articles/chartreuse-plants-for-the-garden https://www.thepaintboxgarden.com/category/chartreuse/ https://www.provenwinners.com/learn/top-ten-lists/10-fabulous-chartreuse-plants-make-your-garden-glow