1. Say you have a fragment that is going to be frequently replace()'d, and thus come & go from the backstack. It has a LiveData observer which operates on some view in its view hierarchy. So, the observer is registered in onCreateView() or onActivityCreated() and uses getViewLifecycleOwner() as the LifecycleOwner to avoid leaking observers when the fragment goes on the backstack and is detached but not destroyed. For example:
 
 ```
    private void setupMyObserver() {
        viewModel.getXyzLiveData().observe(getViewLifecycleOwner(), xyz -> {
            getView().findViewById(R.id.my_view) .setVisibility(View.VISIBLE);
        });
    }
```

In this case, the only reference being kept to the lambda, and therefore to the view it references, would be the reference held by the LiveData due to the observe() call. i.e., neither the fragment itself nor any other objects EXCEPT the LiveData would hold onto the lambda, therefore, this setup should be completely sufficient to avoid leaking either observers or views when the fragment comes and goes from the backstack. Is that all correct, or is there still some potential to leak the view in this scenario?

2. Possibly related: do all 3 of
...

Something like this:
@Query("SELECT COUNT(*) FROM transfers")
fun getCount(): Single<Int>

And I had this call from an activity:
val transferCount = transferRepository!!.getCount()

you should be able to have:

View.OnClickListener clickyClicky = { v -> doStuff(); }

so, if your repository has a roomDb property that is your RoomDatabase, you could have this in the repository:

fun getCount() = roomDb.yourDao.getCount()