Do you mean regular ON/OFF? If so, I’ve already written about something similar… https://reddit.com/r/IOT/comments/17zaapw/easiest_way_to_control_batterypowered_christmas/ka16uej/

However, when it comes to controlling their functions… would need to know exactly what equipment it is and how it works in order to advise.

My wife has a bunch of these that all took 3 1.5v batteries, so I soldered wires into them to run back to a “hub” that plugs into a 5v microsd charger and they are switched with a simple outlet remote. It would be a good idea to make them not permanently attached to the hub for when it’s time to put them away.

You could do it with a mix of 2 and 3 1.5v battery lights but you’ll want to add an appropriate resistor. A 100Ohm resistor should drop it 2v at 20mA. It’s kind of depends on how they’re wired, mine aren’t out yet. I don’t recall if I added a ~25Ohm resistor to the 3 battery ones but I probably should have if there wasn’t one already.

Depends if it has to stay battery powered.

If you’re willing to hardwire it, get a battery eliminator kit like this (get the right one for your device, be careful!) and now instead of a bunch of AA/AAA powered devices you have a bunch of USB powered devices. Get a multi-port USB charger, plug it into a smart plug, and you’re golden.

you could consider using smart plugs with built-in timers to automate the decorations. This way, you can schedule when the Christmas village lights up without modifying the items themselves. It’s a non-invasive and convenient solution for battery-operated decorations.

I hope to power this sort of thing with a PoE network switch. I haven’t tried it yet, but I think you should be able to force a certain voltage over Ethernet. If it works you could automate the interface to be enabled or disabled when you want