I agree, I would never suggest leaving a dog outside unattended while you're not home. There is too much danger and things that can happen while you are gone, and you do not want to come home to a missing or dead dog!
Also, getting two puppies at the same age at the same time is usually difficult because they will bond more strongly to each other than they do to you. Eventually they could start getting separation anxiety from each other, so that they cannot cope when they are separate. Letting them be together all the time will strengthen this bond. So they need to be spending more time with you or other humans than they do with each other.
Most dogs like to be wherever their people are, and that's a good thing.... that's why dogs are more domesticated than any other animal on earth! So if you are inside, you will need to give the dogs some motivation for staying outside. You could hide treats around the yard or feed them meals outside in food dispensing toys. Or you could give them a sandbox if they like to dig and hide treats and toys in the sand to encourage them to explore it.