>>34613992She showed that she had 3 Johto ribbons when she returned, so I doubt she remained in Sinnoh long before going back there and getting her last 2. Remember the Grand Festivals start at a certain date whether the trainers have all 5 ribbons or not, if she didn't get the last 2 in time she would miss out on it.
When the Wallace cup was airing they showed Drew/Harley/Solidad all watching it on TV too, so they were following her progress. It's too bad May never got a special in Johto back when DP was airing, it basically made her whole follow-up arc there happen off-screen.
