Hi Shir, thanks for following up and providing your additional info.
Showing parameter in the Attribute Manager or a custom icon in the Object Manager is not such a big issue: you can start looking at Py-RoundedTube which is an ObjectData derived plugin where all such a stuff (and more) is shown.
That said, the real question is instead to understand what your rig is actually doing and see if it's reasonable to implement the Xpresso functionality from a set of "primitive" functions you implement in your plugin or if would be instead easier to programmatically recreate the Xpresso rig in an XpressoTag then attached to the object generated by your plugin.
Actually this assessment can't be done from here where the final functionality and the complexity of your Xpresso network is unknown.
So far I do see three approches:
start on your own, step-by-step, dissect the code from the example I mentioned above and try to move your steps alone
outsource the task to some paid developer
or
call for volunteers in our very helpful PluginCafe community.
I'm sorry not be more helpful but, as said in the first post, we can't deliver turn-key plugins or scripts but rather help our customer to learn from our resources.
Best, Riccardo