I have managed to get this working using the combination of Dubbo's file plus the Generico H5P embed template. I've only tested on iOS devices, but I'll try to get my hands on an Android device for further testing. It seems as though you've followed the same steps as I have, so I'm not sure where the problem is exactly.
In my case, I've used both the Page resource and the Book module for displaying the H5P content. Page seems to work the best, but I might try the Lesson to see how that looks.
Here's what I did in the course once the file was in place and the template had been added to Generico...
1) In an empty section, create an H5P activity.
2) In the editor, choose the Quiz (question set) content type.
3) Create your questions (I used Multiple Choice, True/False, Drag Text, and Drag Drop).
4) In my case I deselected the Display action bar and frame and the copyright button.
5) Click save and display and note the id number in the url.
6) In a different section, create a Page resource.
7) Insert the following code into the Content area {GENERICO:type="h5p_embed",h5p_id="174"} be sure to change the id# with the one you made note of in step 5. (Easier that what I've just described is to select the box in the Generico template to display H5P embed in the Atto toolbar. This way you can apply the template without having to cut and paste any snippets of code).
8) Save and return to course, then attempt to open the Page resource where the H5P Quiz has been embedded using the Moodle app.
Good luck. I hope this works for you...
