The SLC 5/xx and MicroLogix PLCs can't add drives to their I/O tree the same way that the Logix 5k based controllers can. You can control the drive with explicit messaging, but it gets cumbersome. My colleague at my last place sent a changing speed reference to a Powerflex 525 from a MicroLogix 1400 with MSG instructions. I don't recall all the details, but he had to send multiple messages to affect a speed change and if anything went wrong (and the PLC couldn't always tell when it went wrong), you had to re-send the whole sequence. Also, upon power cycling the system, you had to know to re-send the speed reference or it would "start" but stay at 0Hz until it received another speed reference.
All that to say: yes, it's *probably* possible. Yes, it can be a royal pain to keep it reliable. It will also depend on what you mean by "control via Ethernet". If you just mean adjusting the speed, you're probably fine. With the reliability issues we saw with the MSG-ing, I would probably not use MSG instructions to control the start/stop function. Or at least use a hard wired STOP control that the PLC controls via a relay while allowing the RUN to be a MSG. If that's possible with those drives.