Over the past 25 years of consulting I've had many opportunities to do exactly this, take on multiple contracts at the same time. Unless you can dovetail the projects together you will end up working very long days and more than 5 days a week. One big thing that stands out as a red flag is you comment that you didn't have experience in either of the two fields. That means you may have a steep learning curve and spending a lot more time just getting up to speed on the new technology than you think. The things you don't know can really hurt you. Also on projects like that most people tend to underestimate the effort. My advise, pick the one that is the most attractive (scope or money) and then try to delay the second one for several months while you get the first one moving. Once the first project is well underway it's easier to pick up a second project. Obviously this assumes that you spend very little time at the clients location to do the task. Good luck, but two consulting jobs does not sound like "retirement".

Use IDLE for Python programs. Much better than Notepad+++ and it helps resolve the tab issue.

I'd take a look at Adobe Muse. Last I checked they offered a 30 day evaluation which should be plenty of time to develop a web site. As for hosting the web site I google web hosting, there should be plenty of low cost hosting sites. I'd not try hosting the site at home, you will find that the constant care and feeding of the host computer will be a pain. Much easier to have a cloud solution for hosting that provides backup and support.

LabView does something very similar to this by "wiring up" code modules.