I'm not sure about these changes. Junior Eurovision was already on a couple of hours earlier than regular ESC and wasn't really a bad time for children. Maybe it could have been another hour earlier for the Eastern European countries, but that hasn't been a big problem for them up to now.
Sunday afternoon, by comparison, is just a bad time for television. The kids won't be in bed, but does that mean they'll be watching JESC?
I have no idea how multiple venues is going to work either. I think it's going to look and feel very different to a normal Eurovision show.