I know your question is about the mhl adapter kit, and I don't have an answer for you on that. However, if it is screen mirroring to a TV that you are after, while using your cellular data plan only, no wifi internet, the following may be a solution for you.
I just tested the Actiontec ScreenBeamMini2 with a Samsung Galaxy J7, and it works great. The ScreenBeamMini2 connects via HDMI to the television. The Samsung Galaxy J7 can then connect to the ScreenBeamMini2 using the "SmartView" feature on the phone. The phone detects the ScreenBeamMini2, sets up a Wifi Direct connection between the phone and the TV (no wifi internet needed), and then mirrors whatever you see on your phone onto the TV. This includes Youtube videos, etc. If it displays on the phone, you should see that mirrored to the TV.
For this particular setup, ChromeCast, Roku, etc. were not an option because there is no wifi internet available at this location, so we needed to be able to use the cellular data plan on the phone and then mirror that content onto the TV. The ScreenBeamMini2 turned out to be the solution, for this particular phone. We also tested using a Samsung Galaxy S4, and its built in "Screen Mirroring" feature and it worked perfectly. For both these phones, battery usage goes up considerably when they are connected to the ScreenBeamMini2.
I will note that we had also tested this with an LG Aristo and an LG Stylo 3 Plus and were unable to connect them to the ScreenBeamMini2. Neither of those phones had a menu option on the phone side to make this connection. After downloading several apps from the Google Play Store, none of which enabled these LG phones to connect, we gave up and turned to the Samsung Galaxy J7 and S4, as those were phones we also had on hand to test.