It is always best when getting a new bird, to observe quarantine for 30-45 days, keeping new bird isolated from the other in case of illness. The idea is that when a bird moves to an entirely new environment, it naturally causes some stress. Under stressful times, is when latent illness is most likely to start showing.
It is also good standard practice to take a new bird to an avian vet for a wellness check. Just as most people know you should take a new puppy to the vet, this is no different. Since your girls have already been exposed to each other, it would be a good idea to take them in for a check up.
The slight deformity that causes the toenail to point upward, shouldn’t hinder movement around the cage, but I’d have the vet clip the nail to keep it from getting long and pointy so it won’t catch on things. You can buy natural wood perches which are much better for foot health than dowel perches are. Also make sure your budgie girls have enough toys. Budgies also seem to like swings.
We have lots of information here to get you started. Please take a look into the Stickies and Articles. You’ll find answers to many basic questions as well. If you can’t find the answer you’re looking for, then we’re happy to help.