It can be, just you have to use them carefully because these fields initialize through the onCreate step:

protected lateinit var binding: VB
    private set
protected lateinit var viewModel: VM
    private set

here is another approach:

override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    binding = DataBindingUtil.setContentView(this, layoutRes)
    viewModel = ViewModelProviders.of(this, viewModelFactory).get(viewModelClass)
    binding.setVariable(BR.viewModel, viewModel)
    binding.executePendingBindings()

    subscribeToViewModel(viewModel)
}
open fun subscribeToViewModel(viewModel: VM) {
    //Here you can to do something related to baseViewModel
}

then you can override subscribeToViewModel in child