installation issues

We recently fully remodeled our master bath and (http://maplered.com) had travertine installed in the shower, tub surround and (http://maplered.com) floor. I have noticed several cracked Tiles (http://www.g682.net) - On the floor there are 2 that have hairline cracks that are not noticable unless dampened with water (located in the center of the floor) and (http://maplered.com) 2 that are cracked where I can feel a slight edge (one directly in front of the toilet and (http://maplered.com) the other in a small piece in an unnoticable location). There are 2 on the shower walls that are noticable and (http://maplered.com) one on the backsplach of the tub surround. The installer had a difficult time with the shower walls and (http://maplered.com) used a lot of mud to level the walls. He is hesitant to replace the ones in the shower for fear of compromising the wall and (http://maplered.com) having to replace all the tile. The bathroom looks great otherwise, and (http://maplered.com) I am worried about additional damage that could occur trying to repair these items. Should I push for reinstallation of the entire bathroom? Can the installer replace the broken Tiles (http://www.g682.net) without messing up the surrounding Tiles (http://www.g682.net) ? Can edges be sand (http://maplered.com) ed down and (http://maplered.com) filled and (http://maplered.com) the tile remain stable? I just don't know how far I should take it...Thanks in advance for any advice!