Congratulations on your Admits! Fantastic Job!
I assume you have tried HBS and GSB without a positive result? Sorry to bring that up on your happy day, just trying to understand if you may want to take another shot in R2.
Taking into consideration your success with admits to these 3 schools, i would not expect you having issues with converting into a FT job with pretty much the company of your choice. You have the experience with your age, and you are not switching industries, so you will be building on top of a strong background. The fact that you got admitted so well, means schools are very comfortable with your employability.
I would not agree per se about Booth culture - knowing a number of people who graduated from Booth, or any business school, it is all about what you want that culture to be. Booth has a huge class and you can definitely find the people who are similarly minded and form your little circle. Everyone does in the business school after about 2 weeks. Many programs have a trip/trek before the school starts (Kellogg does a mystery trip still I believe and Booth has options).
https://theboothexp.com - I am assuming you have found this site already? But in any case, I would not worry about people rubbing you the wrong way or getting a bad vibe. It is not like Booth is a magnet or naturally selects boring dorks, and then ranks within top 3 programs

You can absolutely approach schools and kindly request reconsidering their offers. It does not happen often but it happens and when it does happen, schools ask people to keep it quiet, so we have little information about successful reconsiderations but you have to keep in mind that schools have budgets that are assigned for each Round and usually they give those away and unless someone cancels/chooses to go elsewhere (which is unlikely but possible), your reconsideration, will not be granted if there are no funds.
All of these programs recruit well with the top players such as AMZ, FB, INTL, IBM, APPL, and Google. Yes, Haas is close and you will be going to school with many of the folks who have worked (or still working while in FEMBA) at those companies. You will be in the middle of it, which allows to network closer to the corporate office but what I am hearing from folks elsewhere, usually you are well connected with the Booth/Kellogg/etc alums within those companies and they have point people who are in charge of reach out to current students and plucking the best talent early. While it feels like you would likely work on the west coast and so why not move there right away, I am not lobbying for that but it is $100K-$150K cheaper and in case brown substance hits the H1B fan, minimizes your exposure. One thing nobody can tell you is about OPT and Visa. You won't be be needing the STEM OPT until 2022 - that's 3.5 years and a bet potentially on that.
It is an interesting situation. I can find 10 reasons to go to Booth, 10 to Kellogg, and 10 to Haas but you do your MBA only once and you want to do it without regrets and do it well. Where is your heart calling you? Do you want to minimize cost, maximize STEM, or get the Top Ranked school?
P.S. school is never lazy per se. It is always hard work beyond your ability/capacity but one can always find ways to cut corners and coast and shortcut themselves out of a great experience into a 2-year summer camp. There is a funny misconception by east coast people and east coast schools that west coast is lazy because the companies are less formal, people are not at work till 9 AM PST (which is noon eastern), folks wear flip flops and shorts to work, esp in LA, and east coasters are just plain jealous of the quality of life. I would not consider laziness as a concern for Haas, personally. It is a hoax.