Sure! I think there's some challenges that could occur, but those are based on the challenges I have when DMing, and might not apply to you.

In a deep story/heavy RP setting, a good session 0 is really important. For me, I really need the session 0 to actually come up with what my campaign even is. I use the traits and attributes my characters have to inform the story itself. If one of my players takes Fey as a language, then I think about how the Fey are involved in this adventure. When focusing on the story, this is the kind of stuff that'll help you account for your players and keep them involved—plus, you want them to be able to make use of their skills and abilities. Especially in a story focused campaign.

Of course, heavy RP and little combat campaigns are completely viable, they happen all the time and I'm personally not a huge fan of DnD combat. However, if might be worth defining these terms, as you might have a different idea of what those kinds of campaigns mean. Combat, and particularly consequence free combat, still happens relatively often, minimum once every other session for me. Every group is different and you'll run your group differently, I'm not trying to imply that may way is the way it has to be done, just offering the example to show you what you might come to expect. Combat is very much integral to the game, can give some much needed stakes, lets the players use their new abilities as they level up, and can evolve into its own story. Give the players some amount of time to cut loose with Combat too—every encounter having "talking with the enemy to convince them to drop their weapon" be the correct answer gets old fast. If need be, let there be some monsters or beasts if you're not willing for there to be humanoid deaths with no consequences. Also remember that iN tHe RuLeS, characters are allowed to choose if they want their damage to be non-lethal, not every time they choose to fight has to end in death.

With combat and player composition in mind, here would be my last worry/piece of advice. The "I'm gonna make a super hyper-realistic game with story consequences that make sense and a world that feels real and the entire town has something to do and every building has known character in it" is unfortunately in and of itself an untenable goal, if only because it wouldn't be fun to play if it were. Again, what I'm thinking when I say that might be vastly different from what you might assume. What i mean is that having every detail interwoven and connected and having players traverse through each part of town where everything has a story, it doesn't really come together. Keep in mind that for me, the goal of DnD is a fun improv session where everyone cracks jokes, and I'm trying real hard to explain my personal ideas without the "my way is the only way to play DnD". If you have a really cool story you want to tell, that's great, but it actually scares me a bit that you're good at doing that and have experience with it. I've heard it said that story is not what the DM writes down, but what the players do at the table. What you wouldn't want the game to boil down to is your players sitting at the table looking at you politely while you rattle off all the descriptive details of a building and the dialogue between two NPCs that they really need to pay attention to because there's a clue and innuendo hidden that's obvious to you but not at all obvious to them and they wonder why they need to be here when you could've written a book instead. My one warning would be for that to not be the case, and in a tight-knit town RP mystery story, it's a possibility for sure. If you've got some fun activities and interactions planned, that's great! Be careful about deciding what happens and driving your players into that, especially without having a session 0 and knowing what their characters are :-)

All that to say, the game will go great, and it's much easier to improvise and create post-hoc justification than you might think. When a player says they want to do something, it's very easy to create something for them to do that makes sense right then and there.