mobile game FPS drops at first load

Hi, i made a small level with 1 barrack copied in UE4 several times, 1 house copied several times in UE4, 1 tower and 1 longer building. When ever I start the game on mobile(IOS 10 - iphone 5s) for the first time, game fps drops and goes back to normal when it loads a new object. If I add cutscene with the camera circling around the level, the FPS drops even more because it loads the objects quicker.

The objects have 420, 580, 2772, 3570 triangles and they are all imported from Maya exactly like here:

I also set auto LODs to 3 hoping that it would fix the problem but it didn’t. I even filled the objects inside so there is no empty space between the walls(earlier the windows were open so you could see through the houses). Everything else is default. Is there a way to load every object at once so I can avoid the stuttering or perhaps some other fix?