There really is nothing special done for cavaliers as opposed to any other breed
-- a basic check will listen to the heart, breathing, check ears, check joints. She doesn't actually need a one year check up though; she will need to go in for her one year booster a year after her final set of puppy jabs so it is more like a 15 month check up. There's really no reason to take her in at 12 months unless there are problems or specific concerns. That one year booster is very important, however.
MVD is very unlikely to appear in a young dog as it is a progressive disease, so you would really not expect to have any surprises with hearts. Vets also are not that great at hearing heart murmurs, so many people will start taking their dogs to a cardiologist from age one or two onwards for an annual exam -- this would be best practice with cavaliers as half of them will have heart murmurs by age 5 and proper care gives them a much better chance at a longer life. You can often get very low cost cardiologist examinations at cavalier club dog shows -- pet owners are generally welcome -- you will find a list of these heart clinics on the website
www.cavalierhealth.org. You will get a certificate from the cardiologist that indicates whether the dog is clear or what grade murmur the dog has -- it is these same certificates that puppy buyers always want to see from breeders when they say their dogs are heart clear (of course you want them to have been clear at the time of the mating, not a year or two before, and you always want to be sure that the clearance came from a cardiologist, not a vet).
On SM, unless your breeder MRI scanned the parents, or other dogs in her line have been scanned, there unfortunately really is no way she could say whether there is SM in the line. The likelihood is that there is, because it is known that almost no cavaliers are without the skull malformation, and breeders who have been taking their dogs in for scans and who have spoken to the neurologists say that they have been told about half of all dogs are scanning with syrinxes even though they may have no symptoms (see discussions on some of the breeder discussion lists). This level of incidents matches pretty closely with what researchers have seen as well in their studies samples. This high level of incidence is why it is so important for breeders to scan dogs as otherwise they have no idea what they are breeding from in terms of this disease. Just saying you haven't seen it really means nothing -- not least because in my experience, most pet owners do not report back to the breeder when their dog is diagnosed and most pet owners do not stay in touch with breeders full stop. Scanning is expensive though especially in the US so this whole issue is difficult for breeders at this time.