Some of the details may have been lost in translation, but, overall, the parody managed to pull together two distinct TV series and keep their tone while adding to the work.
As an adaptation, Gnomeo & Juliet is a little loose with the original, though it does hit the major points of the play up to when the movie says it’s deviating.
The key elements, ancient astronauts and the Stargate’s coordinates, were in the movie and were fully exploited in a way that was consistent with the events in Stargate.