Make sure you chose the correct device tree. Did you add it to your uEnv.ini config file? Also try to boot a current test build of LibreELEC: LibreELEC nightly downloads. As LibreELEC development for Amlogic boxes is ahead of Lakka, it’s always worth testing it first.
In general, my advice is to find a working LibreELEC build (look for test builds, community builds from forums, etc) that uses a mainline linux kernel, then try to copy the kernel and DTB to your Lakka SD and see if it boots. This will allow you to determine if the DTB or kernel is the issue.
Wifi, Bluetooth (and probably HDMI audio) will not work out of the box, for that you will need to build your own Lakka image with a modified device tree and firmware files. The reason is that there are too many different combinations of Wifi/Bluetooth chips for these boxes and Lakka/LibreELEC just provides a generic build for all. If your chip is RTL8723BS, there is a good chance you can get it working.