Can I install EV3 Education software and Retail software side by side? I have EV3 Retail edition and I like to buy required sensors and build the robots come with the education edition of EV3. I have lots of LEGO Technic spare parts so I expect I can find alternate parts if required.

Can I install EV3 Education software and Retail software side by side?
Yes. I have done this on both Windows and Mac.

I've only noticed one minor problem. On Mac, the program ID is the same for both versions, so only one of the two shows up in the Launcher. However you can still start the other by using ⌘+Space, for example.