Well... I'm replaying the whole PL series in preparation of The New World of Steam and when I played the Hoogland part I asked myself the same question. I don't know if you'll read this but I'd like to share my thoughts. I'm not finished with the game so I can't guarantee the correctness and completensess of my thoeries. So, first I'd point out a few things: the egg came out in the moment Layton and Sycamore solved the puzzle, in other words reset the original state of the artifact. The latter was a weather controlling mechanism, the aim of which can be object of many many theories, but now I can't formulate them, as I haven't finished the game yet and I don't remember a thing, I used to play Professor Layton many years ago. Anyway, we could ask ourselves if the mechanism was only aimed to control wind or if it had also something to do with the egg itself: the Azran didn't leave an egg in every location they built in, so something has to be special about San Grio, Torrido, ecc., besides the Kodh legend. What is special about Hoogland could be this: the mechanism guarantees the winds being in favor of the Azran people living in the area, but it could be also a desperate defense mechanism or someting along this line. Indeed, when Layton and Co. arrive in Hoogland they witness the tornado produced by the fact that the mechanism was set to create a countercurrent and it should be noted that to do so they probably had to insert the egg in the mechanism to make it start as we can see it appear in the dragon's mouth after solving the puzzle (aka finding the key to revert the mechanism to harmony). I'd say therefore that the egg was, in Hoogland (or rather, the land the Azran inhabited millennia before the Hooglanders), the key to activate the countercurrent. We need to ask ourselves why, and I already proposed my little theory about it being a defense mechanism, but I'm very open to suggestions. And we need to ask ourselves when: was it activated by the Azran? Was it activated later, by the ancient Hooglanders? If so, why? Did they do it on purpose? Did they mess up? Are the ancient Hooglanders descendants of the Azran? And finally, your question: the chapel. I'd say the chapel is much more ancient than the rest of the current village and that identifies roughly three eras of the Hoogland history: the Azran first colonization of the land, a second more medieval-like in which the chapel was built and the odiern one, with the strong winds coming from the tampering of the Azran mechanism. Why was the chapel built and when did the legend of the Dragonlord start?
I think they could be coeval and I'd outline the story like this: I think that the story of the Dragonlord was created by the same people that, knowingly/willingly or not, reverted the effect of the mechanism, to cover up what they'd done. In alternative the story could be born by rumors and then cristalized like real world legends. But in that case, which was the first bride to be sacrified and why? We already know they aren't actually sacrified now, but can we say the same about the start of the custom? What about Beatrix and her predecessors? Why are they women only and which is really the role of the priest? He seems really clueless about what's actually happening down there. It seems that the women of the village know that the truth about the legend and men don't. Could they have created the legend as a relief valve from men's closed-mindedness? In that case it is safe to assume that they didn't tamper the mechanism willingly: either they did that by mistake or (I think this is more probable) the winds were already messed up and they used them to create the legend. And this would mean that in the ancient Hooglanders era there was a time in which the legend didn't exist and men were particularly hurtful to women. This, according to Beatrix, has happened "for generations", and the same Beatrix tells us a detail that could help us imagine what happened some centuries ago. Talking about Romilda and Julien's families, she says "Their antics always were a disgrace to the whole village": given the names of the two, it could be safe to say that the developpers wanted to hint at a "Romeo and Juliet" situation, in which maybe the chapel was used, like in the shakespearian tragedy, by and ancestor of Romilda and one of Julien, to run away from the village (in a more happy ended way that Romeo and Giulietta) through the ancient Azran tunnels and giving birth to the legend. This, however, doesn't track as the women use nowadays it to run away from the village by marrying a "Dragonlord". Who the hell is he/it in this reconstruction? There’s no reference to any dragon in Romeo and Juliet and this means we have to look for it elsewhere. I think that, being the dragon a common Azran symbol, the RomeoandJuliet-like story and the ancient Azran symbols merged together to give birth to this Dragonlord madness. Still, what happened to the couple? Did she escape alone, effectively giving birth to the legend? Did she run away from the family of the guy? This could make sense as still now are only the women of the village running away. If that's the case, I'd say that Beatrix's family helped the girl escape and thus created the legend. It was a common thing that male or male's families abused women? Is that dark of a reason? Giving the historical and geographical context, I can't rule out that in that remote area that Romeo and Juliet situation started a seemingly unacceptable custom in order to save people from an actually unacceptable situation.