Isabelle is a contrivance NPC, and her speech welcoming you to V’s town is contrived with the best of them. Most of the other NPCs gathered have substantially more programming to them, but for the most part they are just acting out the assigned scene before resuming their "lives." Isabelle is the leader here, acting out a scene Nintendo's developers visualized, and she leads the assembled villagers is welcoming V, and confirming that V will be the new Mayor. The player is even given a couple of options to refuse, claiming that there has been some mistake. Isabelle dismisses these efforts as a joke. Nothing will do but to accept V’s fate.
There’s a lot of meaning packed up here. The player more or less can’t derail this process, and the options to refuse are included just to emphasize this point. I can’t recall the game ever doing this again, so the scene stands out. Just as meaningful is the letter V receives in his mailbox a day or two later, from the true intended mayor, whoever that might have been. Rather than being upset at being usurped, the true mayor places his faith in you. “And now it’s all up to you! I’m rooting for you!” This scene once again makes the player be the central actor, and underlines V’s sense of agency.
I remember the opposite was true in the Sims. Setting aside that the Player Character in the Sims was not under the player’s direct control, and would frequently disobey orders according to its own whims (remember when I said that the player is not truly in the game in the Sims?), the player had to somehow manage this Sim to unlock features in the career mode, up to and including the freedom to move out. Eventually, the Sim is free to do whatever the player wants, but it’s a long road to get there, and the novelty of the game ran out quickly from that point. Animal Crossing needs only a few contrived scenes to set up its plot points, and from there, the player is free to do whatever the player wants.
V is not yet free of these contrivances, but V can wander around with some early freedom. Becoming the Mayor requires being a resident, being a resident means owning a home, and owning a home requires taking out a loan from Tom Nook. Tom Nook has more of the amiable writing, but deviating from the script is definitely not possible. The scenes moving around town with Isabelle and Tom Nook in tow carry this theme of constraint, but the player is mostly free to do as they like. Animal Crossing is slowly opening up for the player, and once V’s home is place, and the land is marked out for V, the player now has full freedom.
Traditionally, these kinds of restraints are used for teaching the player the rules of the game, but I don’t see a lot of teaching going on. The tag-along characters follow you as you explore, but their knowledge of the terrain is only called for when the player has asked for a clearly impossible request, such as placing a house on a river or town project on the beach. Perhaps the scenes are meant to be symbolic, perhaps as saying that the player is never truly alone. Most players that I have met cringe at this closeness. Perhaps a sarcastic interpretation is the best: V will never get very far away from either Isabelle or Tom Nook, and at least in my town, Isabelle’s town gyroid Llyoid and Tom Nook himself have taken a clear majority of all of my bells.
The scene planting the town tree is momentous, and feels it. As Isabelle explains, the tree will grow strong as the town will, and all of that is up to V to accomplish. Building that tree, and the town around it, become goals that V can work towards at V’s own pace, but it is very satisfying seeing the tree fully grown and strong.
In computer terms this is feedback, a system to inform the player that they are doing something right. Animal Crossing’s feedback is growing in the town square, a clump of pixels and computer instructions assembling itself organically, and the player compelled to work towards it, if for no better reason that to see it grown. Nurturing is a powerful impulse in humans; there’s a lot of clever psychology at work to inspire the player to carry on.
The hoops V has to jump through are not fully satisfied yet, though, and more is to come soon!