If you're doing three fans on a single header, that should be fine. Just make sure their total current is less than 1A, which is the case for most 3x PC fans, and the A12x25 is less than .2A iirc, so you can put more than three of those on a single header. It's safe to use a splitter in that case. I still wouldn't do more than three on one header though.

If you're looking for a hub to run more than three on one header, I use the DeepCool FH-10 and it's pretty nice. Any 3-way fan splitter should work fine. Noctua has some, or you could use something like this.

Edit: the specs page says they're 0.14A, so you could in theory put up to seven on a 1A header but that's kinda risky imo.

When i had my Meshify 2 case, I had 6 additional f12 fans cooling the system. I originally was looking to her this same hub or the other one cooler master has available. Ultimately, settled on these splitter cables that come in a 2 pack.

Yeah, pick up some splitters and drive all your front fans off one header. I usually bundle my intake and exhaust fans into separate groups like that.