Lighting stands are pretty much standard; almost everything that you would be using outside of industrial applications (like "real" cinema, television and theatre llighting) will use "baby" spigot connections (5/8" or 16mm). "Junior" is ultra-heavy-duty for lights weighing in the tens of kilos, and "senior" would be handy for supporting small armoured vehicles in the air - both are well outside of the normal fare for wedding and location work.

As for modifiers, the closest thing there is to a handy universal standard is what's being used on the Godox SK400 flashes you're looking at: the Bowens S-mount for reflectors and modifiers. There are continuous lights available with S-mount built in, including those from Godox, and adapters to S-mount for other LED and hot-light systems. Using a Bowens mount means that you have only one set of speed rings to worry about, and can even use folding parabolic softlights, rather than having to keep a whole collection of rings and rods of different lengths. But that means you won't be able to use a light head that's just a bunch of Edison-base sockets; it'll need to be a proper light head.