Is there any way to get info on clip length (as they are on timeline, one or more selected clips)?
Right now the only way I can see is subtracting start time from end time.

Double click on a clip and you can see it's duration in the pop-up duration window.
For more than one clip you can set an In Point & Out Point. Then move your pointer over the selected zone in the Project Monitor. The tooltip displays the In/Out duration.

Maybe there's other ways but I don't know them.