Welcome.
You are very perceptive. JWs are many times one way at the Kingdom Hall, and another outside of it. The clothing styles inside sometimes really don't match what they are willing to wear at their "gatherings." Yes, it is wrong for an unmarried couple to sit together. Looks bad.
Some of the ones leaving the Hall may be going outside to walk the parking lot to make sure it's safe. Other than that, some are "very important" and have "very important things to do" even though the speaker is supposed to be imparting "life saving information from Jehovah." Some of the elders even get into little groups and talk at the back, or go to another room. You, of course, or all of the plain congregation members, should never do this, or you'd be accused of not appreciating spiritual food. You'll never figure this one out...I know I couldn't and I was "in" for over thirty years.
You are also right about not having much to say except drill you about your intentions.
First of all, they are not encouraged to get an education, so many don't know a whole lot about the world around them.
Second, you are not supposed to discuss much else except "spiritual things" at the KHall. For instance, not sports, and some could be "stumbled" because the may be thought of as violent, or taking time away from Jehovah.
Jws are not really supposed to participate in school sports, nor extracurricular activities.
Not politics, as JWs don't vote, and the only thing they are interested in politically is God destroying all the governments at Armageddon.
Can't talk about the latest fossil discovery of a dinosaur....the JWs taught for years that the earth has only had life on it for a bit over 49,000 years...they are unsure how the dinosaurs fit in. Some even believe Satan put the bones there to confuse people. At best they will say that T-Rex didn't eat meat because he died out before the flood of Noah's day when meat was O.K'd to eat. If you do want to start a discussion on this...it should be interesting.
They don't know too much about medicine, although they will start talking as if they do....they don't take blood (except recently they've been allowed to take fractions of it-the WT decides which fractions, or parts) but then they may not be averse to using a new treatment with cow's blood-yes, it's weird....don't know where that conversation would go)
Doesn't leave a whole lot to converse about.......
The JW you are "friends" with really can't get too close to you yet...right now you are considered "wordly" and if Armageddon comes tomorrow you and all your family who are not JWs will die by fire, earthquake, or some boulders from the sky, the birds will peck out your eyes, and your bodies will lie on the surface of the earth as manure.
Please ask the JW if this is why you are still at "arm's length."
Next, please really take the time to research the history of this religion. I wish I had. I wish I had my thirty+ years back. I noticed some of the same things you did when I was new. There were no personal computers at the time, and no one to tell me these things.
Please get back with us after you've done more research.