Yes option B. I heard that sometimes there is condensation even when there is no issue. U just don't want anything growing behind or in your expensive cabinets.
U shd start with an architect to discuss with u hw to turn yr ideas into a buildable plan that complies with sg regulations. Work with the architrct to get to the URA "written Permission" stage. Then go find a "design and build" contractor.
Locally, you can check out yafen.sg for cheap and good LED lights with 1 year warranty and $10 installation.
If you don't mind the hassle and risk, you can check out Taobao and JB.