What category would OP apply under, since her husband is starting his job in April but she and the kids will want to join in the summer? As he won't have been in his job for 6 months by the time of application, will she go under Category B?
Also, OP, since you want to take your dogs, you will need to get them pet passports, so you'll need to take them to the vet basically right now to start the process--it takes about 6 months start to finish, although depending on the veterinary care they've had to date it might take less time.
OP, you've got a while before you can/have to apply (probably 3 or 4 months, depending on whether you use priority and when you go), so start putting together all your documents and (literally) getting your house in order!
Since you all have US passports, you won't have any problems coming back after your time in Scotland, but I would really urge you to seriously consider staying there for the five years (or however long it takes at that point) so you can get British citizenship yourself. If nothing else, it'll make it so you won't have to apply for a visa again in the future after naturalizing.