Welcome to the board and I hope we can give you some better advice than you've had on managing your young cavaliers.
First off -- you need to separate them immediately and get one or both neutered immediately if this hasn't been done -- a male and female this age absolutely cannot be left together as both can become sexually able to reproduce at any time now and they are way too young to be put through anything as stressful and risky as a pregnancy. They can breed in a second. There are also so many health issues in this breed that you do not want an accidental breeding especially from closely related dogs from the same breeder. On your questions:
1) Please don't yell at your cavaliers. This accomplishes nothing positive in a training sense -- as you are clearly seeing -- but does make them anxious and eventually, afraid of you. You need to train them in a positive way to do what you WANT them to do
(ie what are they supposed to do rather than bark? Have you taught them a 'shush' command? Then what are they supposed to do after that? Do they have good active toys like Kongs to keep them busy? They need some alternative activity, not just to be yelled at when outside). Do you bring them inside so they don't bark? Teach recall and bring them in so they are not distracted. All dogs, including cavaliers, will bark when bored or stimulated by something happening outside. Cavaliers do tend to be less yappy than many small breeds but all are individuals and some are barkers. Cavaliers in particular get quite distressed if left alone in a backyard and will bark and acquire other unhappy behaviours. Two will egg each other on (this is why most breeders do not generally encourage people to get two puppies at the same time -- they will pay more attention to each other than their owners and are harder to train). So in short: this is really a management issue for the owner (eg -- the dogs are an indoor breed and should be inside), not something any dog can really learn not to do if left outside with no one there to manage them.
2) Same with spray bottles -- please don't ever use these with cavaliers. They are quite sensitive dogs and respond poorly to negative 'tools' like this, or yelling, or leash 'corrections'. Theyalso have very large and sensitive eyes that can be damaged by spraying at them.
3) If you don't want things chewed -- don't leave them on the floor and restrict the access your dogs have to specific, supervised parts of the house (especially, out of children's rooms). Dogs this young should not have free rein to run unsupervised around a house -- they need to always be at arm's length and under watch, especially as ingesting things people leave around can easily kill your dog quickly from an impaction or cost you thousands to treat in emergency. Again yelling for this is pointless -- and does not teach a dog anything. Puppies MUST have things to chew -- it develops their jaws and teeth. They are at prime chewing age and desperate for good chew items. If you do not give appropriate chew toys under supervision, they will chew what they can find *out of necessity*. They need constant supervision at this age. They are like toddlers, not teens.
4) Cords are lethal. You can get plastic covers that can be mounted to floors or walls. If a pup chews through a cord that is plugged in, he/she will die instantly and very, very painfully as the mouth will conduct electricity -- they will be fried alive. Ask at your hardware store and I am sure they will help you find the correct items to tack down cords safely. Keep puppies out of rooms with cords unless the pups are at arm's length.
Please have a read through the helpful links on this post. I know they will help:
http://www.cavaliertalk.com/forums/...-only-read-*one*-thing-about-dogs-*read-this*!
And most important: please download this well known (and FREE) book made available to all by trainer Dr Ian Dunbar. It will set you on the right road for training, management and ending up with two well adjusted adult dogs:
http://www.dogstardaily.com/files/AFTER You Get Your Puppy.pdf
The entire website is also a treasury of advice and information:
www.dogstardaily.com
I hope that helps but cannot stress enough that you cannot keep those dogs together if they have not been neutered.