Military Service Member + Federal Civilian Employee Retirement Pension Calculation

Greetings all,

This may have been asked already, but I've been unable to find a straight answer. Feel free to link a previous thread on this if it exists. Questions as follows:

1. How does the federal retirement pension calculation work if I served 12 years in the military (and chose to contribute to a blended retirement system TSP instead of the High 3 retirement option); then going back to school to earn an MD, and planning to work for a federal agency like NIH, CDC, or VA? In other words, is my time in the military cumulative with expected civilian federal employment service?

2. What is the total years of service required to receive a pension? I've heard it's a 30 year requirement, but not sure.

3. How much is the pension?

4. Also I attended a US service academy. I know the 4 years at the academy do not count toward a military retirement pension, but I have heard they count toward the federal employee pension. Can anyone confirm this?

If anyone has any links to official sources on this it would be greatly appreciated! I've scoured the internet to no avail. I can't be the only one with these questions.

Thank you!