I won't answer the first question about the appearance of the seeming smiling face of especially the person nearest the viewer on the Hadar, but rather only touch on some of the other points briefly... for what it's worth, the seeming smile is certainly absent in other renditions.
The 'windfall' of which you speak is, in a number of ways, consistent with some of the meanings sometimes associated with the card, in the sense that there is a 'release' from 'imprisonment' - or felt/ structured constraint. A 'windfall' seems to imply that one is suddenly freed to engage in what one may more freely decide to do.
The flames or bolt's direction, as either from or towards the Tower, is not consistently represented across various Marseille decks. The earlier representations seem to depict more readily flames emerging from the Tower, wheareas some others seem to depict a clearer implied lightning bolt towards the Tower's 'crown'.
In the Hadar, that zig-zagged arrow heading outwards towards the corner 'Sun' is in fact one of the characteristics of the deck which I personally do not like... and find it inconsistant with earlier or more generally accepted interpretative representations. The 'question-mark' forms of the bolt or flames is quite consistent with, for example, the spiralling form of flames as depicted on the Conver. As is the fact that only the top part of the Tower is 'blown off', the rest appearing unaffected by the otherwise apparent cataclysmic event.
As to the 'off-centredness' of the three windows, their representation certainly adds to the sense that here is a circular tower, not a square one. In some ways, this does have some iconographic importance, for it may indicate that this is not a military Tower, but rather, in greater likelyhood, a religious one - though one which is struck down.
I like the way you mention that the curvature of the flames hint at that ever so-important question: 'On what are your beliefs founded?'... beautifully put, and hinting at their abjection.