The issue of tiles popping up after several years is quite common. There are many theories behind this and one of the main reasons is the tiles are laid together too closely at a gap of 1mm or less. It is recommended to have at least 2mm of gap between the tiles, or 3mm. Due to the properties of teh tiles, sometimes the tiles may contract and expand with heat, and if the gap is too little, the tiles will push against each other which cause some of the portion to pop up.

Ground floor don't need, waste of money only.
But make sure pipe redo again because old pipe might leaked or burst anytime after hacking.
water closet look for 10-12 inches, if possible one-piece so easy to wash.
your toilet bout same like my one previously.

Suggest you change wall tiles also, or else difficult to match the color and pattern.
Hacking wise might also hack tio ur existing wall tiles... so u should change one shot instead.
Estimate 4K for ur bathroom (4 side wall tiles to till ceiling + floor tiles + workmanship + material + NO waterproofing).
excluding water closet stuff.

Relocation pipe mostly cost RM400-500 for ur case if u r moving water closet, outlet pipe, etc.