Thanks for your update.
Query 1: "set something like IsEnabled? Or to deny navigation to a tab if it's tapped?"
We have achieved your requirement using the ItemTapped event which is available in SfTabView. Also, we have prepared the sample based on your requirement. Please find the sample from the below link.
Code Snippet[Xaml] MainPage.Xaml
<tabView:SfTabView Grid.Row="1" Grid.ColumnSpan="2" x:Name="tabView" TabItemTapped="TabView_TabItemTapped">
Code Snippet[C#] MainPage.Xaml.cs
private void TabView_TabItemTapped(object sender, TabItemTappedEventArgs e)
if (e.TabItem.Title== "Favorites")
e.Cancel = true;
Query 2: "auto-select a specific tab upon snapping."
Whenever a tab item is selected, the selection will not be moved to another item until we tap on it and we confirm that this is the expected behavior of SfTabView.
Query 3: "VisibleHeaderCount = "3", but as I slide the header left to right, or right to left, I can see 4 tabs"
This is the current behavior of SfTabView and we have taken this requirement as improvement of SfTabView. We have logged this as a feature request, and you can track the status of this feature implement through below link
Please cast your vote to make it count. We will prioritize the features every release based on the demands and we do not have an immediate plan to implement this feature since we committed with already planned work. So, this feature will be available in any of our upcoming releases.
If you have any more specifications/suggestions to the feature request, you can add it as a comment in the portal.