Hi sanjali, sorry I didn't see this post earlier - were you able to solve this design dilemma yet? How'd everything turn out?

Just a little ceramic information to share as a potter. Vitrified simply means the clay has become glass like by being fired to its proper maturing temperature. Usually ceramic tile means it is a lower temperature clay like earthenware or terra cotta. Porcelain is fired to the highest temperature and is more vitrified if you will. This usually means it is less porous to to absorb water and harder. Low fired ceramics with glazes much darker or lighter than the clay body will show chips easier. Rectified has to do with making the edges precise enough to fit smoothly together for less grout lines. So porcelain cost more to produce but it is more sturdy. All clay tiles should be vitrified.

Yes if the tiles are not cracked and are in usable condition. You can also choose to leave minimum gap between two tiles.

Most likely these fissures would be there before installation. Yes, it is feasible to replace the granite piece but the workers have to be cautious. You may try offering them extra money most likely they will do it. Before buying your newer slab check thoroughly for fissures and cracks. Thanks, Amit CORNERSTONE DESIGNS Bangalore