It’s look like I’m missing sth extremely obvious 
I’d like to have empty persistent level. All assets, including walking surface, would be stored in sublevels.
The problem is that streaming of level with terrain/walkable mesh happens after event BeginPlay. So player is spawned, but level for him is loaded a bit later
Currently I put only Player Start to the persistent map. Player spawns properly on mesh (stored in sublevel), but player doesn’t move (although nothing been changed in blueprint - it comes with top down template).
I neve had such issue with UE3.
What am I missing, guys? How to divide data properly? As I mentioned, I’d like to have persistent w/o data (it would only serve as map root).
Your movement might be constrained to a navmesh. If you have nothing in your persistent level, then your navmesh will be tiny. Try rebuilding navigation on all of your sublevels as well as adding a Navmeshbounds volume to all of your sublevels in the walkable areas.
It is possible to keep persistent level almost empty. When game starts sub-levels which have type “AlwaysLoaded” will be loaded and visible before BeginPlay event. Sub-levels of a “Blueprint” type by default are not loaded, and should trigger loading on user events which is obviously after BeginPlay event. But you can make them loaded and visible at game startup as well, using “Edit Properties” command in “Levels” tool and setting “Initially Loaded” and “Initially Visible” to true.