Congratulations on adopting your girl!
If you want to use the pee pads only for inclement weather, I too think that would be confusing for your baby to only have the pads sometimes. My boys are pad and outdoor trained, but they always have the pads available.
I have a friend who trained her Yorkie girl to use pads in the garage during bad weather. Having a designated area that seems outside of the home is usually the only way to successfully use pads only part time.
If you want to pad train, limit her roaming room to a smallish area with the pad. Use keywords like "potty here." The disposable pads have a scent infused to attract the dog. When she goes on the pad, praise profusely and give her a small reward. Do the same outdoors so that she associates both with good potty.
Teddy was 100% outdoor trained when we brought him home at 8 months. I successfully trained him to use the pads. Convincing him to poop on the pad was the hardest part. I had to line up several pads and corral him. When he finally gave in, he was relieved to see how happy I was and that I took care of disposing the poop right away.
