Good morning.
I have many years (decades, actually) designing and developing database applications as a freelancer/contractor to a number of blue-chip banks, telcos (etc.) worldwide.
I have worked on just about every kind of OS in existence, but PostgreSQL I have been working with primarily for over seven years. Windows I have been using since v3 (8 bit, over DOS) in the mid-90's. No problem there.
In answer to your questions:
1a) A clean Win10 PostgreSQL install will be a matter of minutes. An export of (up to the scale of a million or so records) and refresh to your new system I'd be very surprised if it took more than an hour or two.
2a) Pushing this out to a Heroku build (which, along with bitbucket, I used almost exclusively all of 2016) is mostly a matter of getting your buildpack right. Once you have that set up, it requires little or no maintenance.
Experience:
1b) Django. Well over two years, all up.
2b) Postgres Over seven years.
3b) Heroku. One year.
4b) Windows. Over 25 years.
5b) Visual Studio. Exactly none. I would use any freely available (atom?) editor for DB->Python work.
6b) Normally $30USD/hr and up. However, I am looking after my daughter and can only guarantee 20 hours a week (at a minimum...) so less.
7b) A week, maybe two depending on documentation, automated testing or any other frills required.
8b) Out of hours, Europe: actively preferred.
9b) I'm English, fluent.
10b) I can't think of a platform I'm not available on.
Free to discuss any time.