Hi there, welcome to the forums and congrats on adopting your piggies!
It's really great to hear you adopted and are doing your research. You've done well to find this site - you will find everything you ever needed to know about piggies on here, we're always happy to help.
I'm glad you said they've been properly treated for mites, so they should be pest free now. I would recommend finding a
cavy-savvy vet now, so that you know someone reliable in case they ever get ill. I think it would be worth getting them checked out just in case.
A lot of people recommend weighing your piggies regularly too, so you can see if they start gaining or losing unusual amounts of weight.
Can you clarify about your porch? I assume this is an indoor room? If so your piggies should be fine as long as there are no drafts and the temperature is fairly stable.
Your piggies should enjoy munching on the lawn in nice weather, but we don't recommend you leave them out there. There are far too many risks - pests, predators, humans etc. Your piggies should only be outside when you can supervise them.
Hutches can be a problem. Firstly, they are impossible to keep clean because the wood absorbs urine. If you are going to continue using a hutch I would suggest putting something waterproof on the floor (eg coroplast - called correx in the UK) just so it is more hygienic. The other problem is that most hutches are far too small. Can you measure the
inside dimensions of your hutch and tell us how big it is? 2 Guinea pigs need at least 7.5 sq feet of floor space, preferably more.
Your bedding sounds ok, but I think you need something over the puppy pads in the main area. Aleternatives are all care fresh, aspen or the fleece method. I love using fleece (over towels or mattress pads) - I think you could use vet bed in place of the fleece but you would still need something absorbant underneath it. Check out the fleece study in the stickies (bedding section) for more info.
Hopefully your piggies shouldn't have any problems as a result of not getting veggies, although it is worth keeping a look out for signs of scurvy. Just start feeding them a proper diet now and they should be fine. I don;t know if your food is any good (someone else might be able to tell you). If not you can order Oxbow online.
Check out all the sticky threads for loads of great info. Enjoy your piggies!