It sounds like you're just struggling while on your way to your own 'black triangle' moment.. It's a good thing! The reward is totally worth it!
Next step, tie all the solved problems together into a working solution. Relatively speaking it's actually the easy bit.
From your answers it would appear that you are on the brink of seeing your idea come to fruition.
If it is any help, try to integrate each technical area one by one into the complete application. The incremental results might give you that extra shot of energy seeing the finish line so close.
Good Luck!