Houseright

Concrete boards are a gimmick. use the correct plywood prime it before tiling and use flexible rapid set adhesive. fix the leak first mind on bath or your problems will only continue. make sure to mechanically fix the plywood and but up tight against existing flooring. the use of flexible adhesive should allow for movement.

Yes. dont forget to use pipe inserts. flexible pipe allows for awkward fitting and barrier pipe has two layers of protection against cold and punctures and can be used on heating as well as service pipes.

Expansion gaps do not have to be all the way around the floor but you do still need them on at least two sides to allow for movement. regards kick boards just fit underneath a ways and cut down kick boards to fit on top. job done.

Slowly and with care. try to use a wood saw or a long retractable stanley knife. sounds like it could be stuck down with silicone.

The company are taking liberties for sure. lamintae flooring is never suitable for kitchens or bathrooms because there is no such thing as waterproof laminate. nor is laminate suitable for pets because it can be scratched over time regardless of what they tell you. remember that a lot of companies will tell you what you want to hear to sell you their product which is disgraceful. in an ideal world you should remove skirting then fit laminate and refit skirting on top allways allowing 5 mm for expansion. you can glue them together carefully and this is time consuming as you would need to ratchet them together whilst glue sets. this method is usually reserved for flooring such as bamboo or oak and the like. in most cases if there is a gap its because the boards are not clicked together square, the expansion gap is too much though unlikely or the laminate is rubbish more likely. as an alternative try using vinyl boards in kitchen and bathroom as these provide a much better water resistance than laminate. in any event as a consumer you have the right to return any unused product to the store within a year and they can not refuse by law. hope this helps