The plumbing and piping seem to add up to RM2k for a small bathroom of 7x7. Abit much I think. But since this is a small job, it tends to be expensive.

As for tiles, I recommend u consider using porcelain tiles at least. The cheaper ceramic tiles have high water pass thru rate, I think like 10%. For floor, consider using a homogenous tile with a non-slip surface (MML Starcrest). Price wise in KL for a 2x1 about RM10 per pc. My sister in law put in smooth floor tiles, and it is just not very safe esp for old folks and children. Based on your numbers, u are tiling walls up to 6 ft or so. Better to do all the way up, less messy long term.

Your quote dont have basin cost and also ventilator fan....

If u have 2 more toilets to do, it cld be cheaper to do at one go.