I've looked at the first issue before and recall the ordering, from most to least intelligent, going agnostic-atheist-uncertain believer-firm believer, but am not able to find the relevant post, so we'll recreate it here by tapping old faithful, the GSS.
For contemporary relevance, all responses are from 2000 onward. To avoid racial confounding only whites are considered and to avoid language fluency issues only those born in the US are considered. Mean IQ, as converted from wordsum scores assuming a white mean of 100 and a standard deviation of 15, by belief in God (n = 4,734):
Parenthetically, "firm believers" make up more than half of the respondent pool, which is why the results appear at first blush to skew above an average of 100.
Without passing comment on the speculative reasons why it might be the case, the second assertion can be evaluated by looking at dichotomous responses to the question, "Generally speaking, would you say that most people can be trusted or that you can't be too careful in life?" Using the same parameters as above, the percentages who say that most people can be trusted, by belief in God (n = 5,294):
If being trusting of others is considered desirable, the ordering runs the same as it does for intelligence. Agnostics are more trusting and more intelligent than atheists, but atheists are more trusting and intelligent than theists (as gauged by the metrics employed here, anyway).
By definition using natural methods to discern, discover, or comprehend aspects of the supernatural are likely to come up short. Some people interpret things as being revelatory, and many more benefit from--and realize that society benefits from--the aspects of unity and teleology derived from trying to make sense of the supernatural. I don't get much out of that myself and find that stoicism applied to the 21st century works better for me, but everyone's mileage will vary. Find what gets you the farthest and ride it.
GSS variables used: YEAR(2000-2014), GOD(1)(2)(3-5)(6), BORN(1), WORDSUM, RACECEN1(1), TRUST(1-2)