Thanks for your comments.
Yes, of course, I will use a Y splitter as well :)
I have GS1005HP 5-Port GbE Unmanaged PoE Switch | Zyxel, which should be able to run both camera and IR light. It is a PoE+ and it has 50W in total, shared on 4 ports, max is 30W per port. Im running Dahua cameras...