Can I store a dry chemical extinguisher in an area that temperatures get down to freezing or lower?
no not at all this person is a total stranger to you and who knows if the guy is telling your husband anything that is true, you got to remember they are living in a video game fantasy world.
Nope. The news is littered with stories of crimes that were committed after naiive people decided to meet up with friends that they met online. Pedophiles and criminals play video games, too! You're right to think of your family's safety first. (It also sounds like your husband needs to grow up.)
No you are not. Although for the most part the people addicted to these online games are normal red blooded men, I can totally picture some nut or serial killer siting at home in a dark room, playing these games day and night and then coming to spend the night and murdering your whole family.
Evolution is an explanation of facts. Theories, in other words, are based on a collection of facts and what a theory does is attempt an explanation of those facts. For example, at the Grand Canyon you can find mountain sides where you can see fossils buried in the layers that make up the mountain. Take any one of these fossils and you'll see how at the lower layers they lack a spine, or legs, or arms only to see them appear on the same animal in the upper layers. How do you explain that? Evolution is the most accepted theory in this regard while Intelligent Design, or whatever you want to call it, can't explain these facts.
Honestly I wouldn't let him. Your husband may think he knows him, but how well can you really get to know someone on line? How do you know if he is an honest nice guy or (pardon) a total weirdo? I would never let someone unknown anywhere near my child, and to be safe you prolly shouldn't either. If your husband wants the guy to visit, that is maybe OK, but don't be in the house with him with the baby go stay at your Mom's or a friends. Put your foot down, don't let him stay the night. Let the guy get a hotel room, they aren't that expensive. And when the guy is visiting, check up on your husband every once in awhile just to make sure everything is ok. Let him know he needs to answer the phone when you call or the cops'll be at your door. I hope it helps, good luck and be safe!