http://www.telerik.com/products/windows-phone/overview/all-controls/loopinglist.aspx

Provide API or another approach to achieve synchronized trackballs.

If AllowFocusWhenDisabled is set to true the control should be edited through the keyboard.

Create an expander control that can be used in Universal Windows Apps.

Enable drag and drop between cells of different rows in the DataGrid for UWP. Or a way we can develop it ourselfs.

ListView: Expose setter for SelectedItem property and implement it, so that setting this property applies the corresponding style to the selected item.

Declined: The SelectedItem property has public setter. Setting it makes the style be applied as expected on the item.

In addition to including the SDK examples in the installation submit SDK examples for UWP in GitHub in a similar matter as the Win 8.1 ones

The SDK examples could be found on the following link in Github:
https://github.com/telerik/UI-For-UWP/tree/master/SDKExamples.UWP

Expose API to limit swiping in a single direction. This should disallow the user to even start swiping in one direction, keeping the functionality intact for the other.

Enabled the control to load its ExpandableContent using the x:DeferLoadStrategy="Lazy" attribute.

Cannot use spaces in editors within groups.
Instead space triggers expand/collapse state

Implement Day view for calendar with the ability to visualize events, so that in fits in scheduling scenarios.

Available in the 2018 R2 release.

Declined: Currently UWP does not have an ImageEditor control. On the following link you can find a feature request where you can vote for introducing such a control and track its status: https://feedback.telerik.com/Project/167/Feedback/Details/201118-new-control-image-editor-port-to-uwp

Available in the R1 2018 release. 

It works nicely with touch, but one would expect to be able to scroll using the mouse wheel on a mouse/kb PC.