Hi kqed,
That sounds like an interesting problem to solve 🙂
We’re a bit limited in terms of how much assistance we can provide for custom development tasks, but I want to highlight first of all that the meta key for the end date is actually _EventEndDate (note the leading underscore). If changing that by itself doesn’t help, might it be possible to steer away from tribe_get_events() in this situation and use WP_Query directly?
If you reference the orderby section of the WP_Query docs you can see it is possible to order against a meta key:
codex.wordpress.org/Class_Reference/WP_Query#Order_.26_Orderby_Parameters
If that doesn’t work it may be that you need to do some more advanced work and change the where clause using other filters and hooks provided by WP_Query.
I hope that at least provides some paths you can explore – and good luck!