Try responding to the first point then.
By which I assume you mean:
Let's assume that believing in God makes you more happy overall than not believing in him (which is supported by the psychological research, although may be involve other variables inherent only to religion).
As you say, this is supported by the psychological research, so I don't really need to /assume/ it.
My initial reaction is to consider the short-term effects versus the long-term effects. For a somewhat exaggerated example, if belief-in-God makes you happier, but the mental processes that lead to this belief also lead to actions which result in you dying at age 30; while a lack of belief in God means you're not quite as happy, and is the result of mental processes that result in you dying at age 90... then depending on how you measure things, the second case results in more total happiness than the first.
And I think fact checking would prevent us from the theory I initially presented to your OP. After all, the veracity of all theories is conditional on whether or not it fits a collection of facts, right?
I wouldn't say just /any/ old 'collection of facts', but 'the sum of observable evidence'. (I've had bad experiences with hucksters cherry-picking the one study out of a hundred which, because of the nature of statistics, could be interpreted as supporting their claim, while ignoring the 99 studies which falsify it.)
True, but Aunt Helen sure doesn't know the truth unless I share it.
If your hypothetical Aunt Helen inaccurately believes that a description of her appearance that is meant to be truthful is, instead, meant to be an insult... then that more fundamental false belief will need to be corrected before the rather minor false belief about her current level of beauty can be dealt with.
Think about hope in your own life. I may hope (as a counselor) that I'll end up this long string of clients after this last rambling one, even if I find out later that this wasn't the case. Hope means putting your bet on a possibility, and the vast majority of all possibilities are false, given that only one has to be true in order for actuality to exist.
Hrm... I don't think I can properly deal with this point without referring to probability theory, specifically Bayesian Inference; and that can take a while just to lay the necessary groundwork. So, for now, I'll just offer a link to "An Intuitive Explanation of Bayes' Theorem" at
Yudkowsky - Bayes' Theorem , and, since very few people actually bother reading that, the much more digestible, if not as completely relevant, "Twelve Virtues of Rationality" at
Twelve Virtues of Rationality .