old wiring is better for powerline devices as both circuit breakers and RCDs have considerable inductance in them which acts to block high frequencies, whereas old fuses are just a piece of thin wire.

AC lite is a good choice if you dont need to have real power over ethernet and are happy with using their injector to power it.

They have an app (android at least, not sure on ios) that can config them up and then just leave them running. The controller is handy tho so you can see what devices are on it and how much they are using etc. Once you have one and see how good it is compared to the terrible fritz wifi you will probably want a second one. That is when the controller starts to be a lot more use for managing them as a set and keeping the ssids and wifi keys constant etc.