I don’t know that the splitter adapter would be rated for that amount of current, is the main concern I would have. It’s probably fine. I would personally get one of these and run the separate wall warts individually:
These cords do a good job of keeping wall-warts bundled together and are space efficient for power strip access. There are lots of benefits to a more distributed power arrangement – easier to debug if you have an electrical or installation issue to figure out, easier to replace a bad wall wart or keep a spare, etc. So I wouldn’t be super attached to the idea of powering everything off of a single source. At least not for performance concerns.