Your credentials, while impressive, are not sufficient to prepare you
to be a financial advisor. They do, however, prepare you to be an
ultra-HNW retail broker. You should decide early on what career path
you wish to pursue.
Regardless, with your pedigree, you should contact the private wealth management (not “Family Wealth”) divisions of any firms before proceeding further (GS, Credit Suisse, Barclays [new] and UBS).
The non-PWM side will limit your ability to leverage your credentials. Generally the PWM divisions of firms are separate and have superior resources, access to product, and much better support. (The downside is that you won’t be allowed to service accounts smaller than ~$2million.) The Dean Witter / Smith Barney side won’t have sufficient resources / personnel to help you compete for the business you’ll have a shot at early on and will really limit your ability to develop the type of business you’ll have a chance to do. There’s just not enough SAs, budgets are too small and compliance is too understaffed and bureaucratic. (Sorry guys, it’s true.) You need to have assistants booking your appointments and a decent office to compete for the types of people that you will have a shot at getting (or blowing it with) early in your career.
Also - a PWM division will allow you to do some institutional business early on in order to make your numbers. The compliance regime and limited platform (retail brokers don’t have level 2s or Bloombergs,  for example) make that effectively impossible for anything other than new issues. You may need to reach out to hedge funds, pensions and other former clients to keep you running while you build your business.
You should get some syndicate at a PWM which seems to be important in the financially sophisticated, ivy league world. (I can only speak as an outsider - I went to a state school.) As a rookie at any of the retail operations - you will get nothing - absolutely no loss leading products. This makes it difficult to get through the door with other Harvard MBAs, people from GS, etc.
You should also directly check out several of the local RIAs by contacting Charles Schwab Institutional and indicating that you’d like them to help you pair with an existing firm. Based on your credentials, you’ll get quite a number of interviews even if you’re in Greenwich or something. Starting at an established RIA is probably better in terms of lifestyle and pay than even MS PWM and it’s certainly superior to the retail brokerage channel at MSSB. But, unlike a brokerage, you won’t (or aren’t likely) to have any interesting products to develop relationships with early on. Unlike a brokerage, you’ll have the a great deal of freedom and flexibility.
Regardless of what you do, in real life, you should talk to a number of successful financial advisors from each world separate from the recruiting process to get an idea of what the job is really like. As hard as this may be to believe - some managers might slightly misrepresent their offices.