Cats have super sensitive senses. If they’ve lived indoors for their entire life the outdoors is a sensory overload to them. If you could allow them to go out in a screened outdoor porch whenever they want to, then they can slowly, safely acclimatize to the new world impacting their nose and ears. Don’t force them out. When my cat was small I only let her out when I could go with her as I had eagles, hawks and owls, any of which will kill small cats. There was also a dangerous neighbor’s dog. But once she showed me she was alert to the dangers and could shoot up a tree, I ceased worrying.
On the other hand, if they have no claws don’t ever let them out. They’re defenseless, except they’ll still try to use their non-existent claws for defense.
One of my cats had been completely de-clawed by her original owner, but she had a right hook that made my other cats show her due respect.