I know that Kaede's red is a different shade than Riho's one but we'll still see the same red during concerts on the glowsticks. I think it'll be kinda disturbing...
I would have prefered they give the red color to another girl once Riho left H!P because we all know that she'll return next year and it's kinda ambiguous I think to have another Morning Musume member with the red color even if it's a slightly different shade...
I was convinced Kaede would get the green color. I was so wrong! >__<
In fact, I've always considered red to be the color of aces. I would have prefered Sakura to get this color than Kaede. I don't see this one as a future ace but I can be wrong.
And about Riho's location, we all know she's in USA since a japanese journalist tweeted it. I personally think she's in LA since this is the capital of dance nowadays and Maria said, after Riho's graduation, that she still wanted to go to Disneyland California with her. If Riho was in New York, Maria would want to go to Disney World in Florida instead. That sounds quite logic to me