There’s some differences between the platforms as it applies to UE4, it’s mostly rendering and physics stuff. You can test mobile stuff now, since it’s already in the engine. As for consoles–for the most part things will be the same as developing for PC. Of course, the hardware has limits, so something on a high end PC might not run well enough on a console.
Just know however, that it’s not a simple matter to get a console development license, you have to prove that you’re capable of developing something for release. In your case, if you and your kids are just messing with game development and just want to try it out on console then they’re not going to give you a license because they want experienced developers to release games on their console.