First off-for outside you need frost free tiles. If you use regular tiles the freeze thaw cycle will cause the glaze to crumble off. If you live in a warmer climate like florida you might be able to cheat that, some people have luck and some dont. There is no problem with leaving tiles whole, But I would be careful with the broken ones if my bottom were going on it, LOL nd make sure I tumbled them to soften the edges. I would also give that cement a good cleaning scrubbing well with a brush to ensure that no deposits are on it that would interfere with the adhesion of the mortar.

Your table and bench look really nice. The suggestion that I would make is: put the tiles closer together, don't leave a lot of room where the grout goes, like where you have the broken ones. It will look very nice when completed. Be sure to post a pic..

I like your layout, and w/the broken tiles to fill all the gaps, it'll look really pretty. I don't think you need do anything w/the edge - just smooth the grout around the edge when you apply it. Welcome to the forum.

You just got info/input from 3 of the best..they said it all!! Welcome!! All I'm gonna add is have fun w/it!!

I learned after I did a outdoor project what could happen because I used indoor tile. I coated the entire project with Zinsser's Patent Shellac.

I do not know if that is a option or if it is a recommended thing to do, no cracked or flaking tiles at all. All I can say is it worked for me and it has been 5 years.

The other plus was the grout stayed a beautiful white.