Qsys / Platform Designer - Using IP (i.e. FIFO) in Custom Component

I think creating reusable .qsys files is a more viable strategy here than trying to cram IP into a custom component. The interconnect will get created whether the IP is in a custom component or in the general system, so I'm not sure what benefit you're looking for here. You can have a library of .qsys systems just like you can have a library of _hw.tcl custom components.