I think a pale grey would look beautiful!

Paint all the way!

Great idea introducing the grey over the existing render. You will find it will calm down the redness of the bricks at the front door area. Paint the posts by the front portico area the same colour as your down gutter and fascia, that dark blue.

For the render cladding areas, I would suggest a colour such as Dulux Excelsior, or a lighter version is Warm Granite. They both have a slight undertone of red which would tie in with the bricks nicely. Good luck

There are different solutions to chose.

Im a bit mad so I would do all the paint work black, and make all that blue disappear with Dulux Terrible Billy. Fantastic colour. Paint the front door a colour that picks up the tiles.

Don't paint your brickwork... the tones of the roof and brick work would soften the black and look stunning. Then redo front garden ...greenery looks fantastic against black.

AND take a photo/photos of your house , print on a4 paper and colour in the areas to paint and see what it looks like.

Otherwise paint all the blue in a strong or soft green to match the garden.