In built are a lot more tricky than freestanding don't confuse the two.
I would buy the fridge freezer as the kitchen manufacturer usually aligns their units in split 50/50 70/30 etc with the cabinet units they sell and you have to vent and jack up, aligning the doors is difficult as well as getting the sliders to work.
Fitting a dishwasher is tricky as it will have springs to tension the return and stay down, most will have a template you selotape to the back of the unit then drill.
I think a washing machine will just sit behind a hinged door.
I have just fitted my whole kitchen with Baumatic, double cooker, 5 burner hob with wok burner, extractor, 50 / 50 fridge freezer, dishwasher, microwave, glass splash back, and a griddle plate, cost £1300 - 1400 direct from Baumatic delivered, there's nothing wrong with any of it, yes the sides of the cooker and dishwasher seemed a bit flimsy but all still working and doing fine modern looks and simple.