Why all these complications?
The aggregator isn’t necessary, it’s just a convenience. It’s perfectly OK to subscribe to individual sites and feeds and being your own aggregator for yourself.
A reader (to read what other sites published) and a publishing solution (i.e. your own site) are two very different things. You can, of course, have your website do both, but you don’t have to. And you don’t need to bolt them together simply to be able to do “likes” and replies while you’re reading (although you can, of course): having them interoperate (via MicroPub or some kind of hooks) is also a viable option.