I think if you select a wall color that is too well coordinated to the tile, it will only bring out the vibrant pattern in the tile. So pick colors you like. Let your personal style and the vibe of the rooms dictate the colors. Your walls, furnishings and accessories will take center stage so you won't really notice the tile. Area rugs will down play the tile too. Ceilings are a great opportunity to add color also.

Well, there are basically 2 ways: Straight and diagonally. This is assuming all floor tiles are the same size and square, of course. If you have a rectangle, then you already have more choice - horizontally or vertically. There are some mix and match sold as sets or created by the person buying them that make the options virtually endless. Heck, you could have chevron floors. You can make a tile "rug" in an area. You can make stripes with a different contrasting tile. You could lay them like parquet floors. You can add little glass tiles in the corners. If you are working with rectangles and/or mixed shapes, the sky is the limit.

The tile person should be able to demo and replace the tile. Most should know how to do drywall sufficiently enough to clean up their own mess. Most wallpaper people also patch walls and paint. There will be other things that need to be done, but between those two people they can lead you in the right direction. Just make sure to get this information before you start with a clear understanding of what those two are willing to do, and have it all planned out ahead of time. They may, for instance, be willing to remove a toilet to wallpaper behind it, but then have a plumber put it back.

I'm in Toronto too. When we needed smaller tiles, we ended up buying mosiac tiles which are small tiles glued to a mesh backing. We just cut the mesh and used them individually. What is on the website is a small fraction of what a big tile store has. I think you need to call or go in.