Frequently.
That’s actually a different Chris, not me. 
This may or may not be true, Seth may have said “many” at some point but I do not believe he ever said “most”. However (for the others in this thread) it isn’t of importance either way, as the beliefs exist in the present and are easily changed in the present, the date of their formation is really quite irrelevant. It could be helpful to know why you adopted the belief at that time, but what truly matters is why you hold the belief now. In many cases the answer may be, “well, I believed it at one time when it made sense, and I frankly never questioned it since”, and now, having re-discovered it, you realize there is no good reason to hold it, i.e. it no longer makes sense, and so it is discarded.
In a certain context of study these statements are true, and the system and belief may indeed be quite helpful. Beliefs will quite often have both emotion and imagination (i.e. particular mental pictures) attached with them. However, back to Seth’s teaching: belief generates emotion, belief generates thought, and belief activates imagination. Belief is primary, not emotion. We have emotion, we have thoughts, and we have belief, but we are none of the above. Not identifying with our beliefs, thoughts, and emotions is of utmost importance. Realizing that emotion and thought are the effects and not the causes of belief is highly important. We can use both emotion and imagination in a deliberate conscious manner to alter belief, and that is often how it is done. Without this deliberate conscious action on our part however, they are driven by our belief. Which is why it’s quite helpful to look toward our emotions and thoughts on various subjects to somewhat easily identify our beliefs, and then work at changing them.
Yes exactly.
Yes!
It’s true that precisely when the belief was adopted may be long forgotten (or it could have come from a complex of pre-existing beliefs). I just want to reiterate for readers that this is not important, as the belief exists and is freely examinable in the present. Do not go looking for the source of a problem in the past, this is not helpful, and is instead quite disadvantageous. What matters, the only thing that ever matters, is why you believe it in the present. 
And this is available!
This is good advice.
Cheers all.