Asana and GitHub just released their own Boards feature, how convenient is that for a Trello sync?
Unfortunately, their boards are not yet available through their APIs but we're working hand-in-hand with them to release these new features as soon as possible.
If you sync an Asana board with a Trello board, lists won't be synced properly. What will happen is that every opened Asana tasks will fall under the first Trello list and all the complete Asana tasks will fall under the last Trello list of your board.
GitHub Projects work with "notes" and note issues, directly in a repository so you just won't be able to see it in the repository list when you create a new sync.