which elytra fly plugin is to used for the plugin

This doesn't make use of an Elytra fly plugin. It simply checks if the server has set the player to be flying, and if it's at a disallowed place disables flight.

The Elytra blocking feature only blocks vanilla Elytra movements, though I suspect plugins allowing for flight with an Elytra would probably be caught up by the flight-blocking functionality -- hard to say without testing specific plugins.

If AWF doesn't work with as expected with an Elytra fly plugin, let me know and I'll look into it!

Is there any plugin which gives elytra to ranked players on join (no rockets)