If you are going to use a brand, I recommend you use that brand as it was intended- as a system designed and tested to be used together, especially if that is what the manufacturers instruct you to do.
Some brands, such as Gelish, openly advertise that their top and base coats can be used happily in conjunction with other brands. I wouldn't as a personal choice, but that is within the scope of their manufacturer's directions if techs choose to do so.
CND Shellac however, is not a brand that can be used interchangeably. CND instruct that the system must be used together, mostly as it is a different formulation than other gel brands. This includes also using their branded lamp, and not a generic one or another company's gel lamp. It is LED curing, but again, only specifically in the CND LED lamp.
And this is not directed at you- but I'm waiting for the naysayers and the techs who think they know better than the product manufacturers to now come out of the woodwork and disagree
Also re: soaking off, I have heard of people soaking off in a bowl, but the vast majority of common sense people use foil wraps or soak off clips, as we are trained x