PVC foam board is not suitable to build wardrobe, when the length get longer without support it will sag under it's own weight, when you put more cloth on it then it will sag even more

i dont know what you mean by using AB screw and not drilling, if you use 2-in-1 or 3-in-1 you will need to drill hole to fit the fastener, if you use pocket hole you will need to drill also, if you use screws alone, you will need to drill pilot hole too, you can directly drill a self tapping screw but will have a chance of slippage or break the melamine layer

if you want custom made wardrobe better to approach the carpenter or designer and let them design it to your liking, dont worry about the small details like what screw to use, it doesn't really matter

and if you want anti fungal, then make sure the water and humidity stay out of your wardrobe, unless you willing to coat your wardrobe with polyurethane which is waterproof and fungal proof, but will cost you a lot of time and doesn't look nice compare to the original look


those HPL and melamine board is all chipboard, melamine sheet is pressed with the chipboard during production instead of manually stick on using contact adhesive, hence faster production and lower labour cost, theoretically melamine chipboard like HPL is more durable and less prone to melamine sheet separation, but in reality when they exposed to water for some time they both will expand and fail