It will depend on the song. Since my First Lady was Praise Team Leader, a lot of the songs we sing are more suitable for her vocal range (including some Israel stuff).
As the current Praise Team Leader, I sing the 'lead' for some of our songs, now. Again, it depends on the song. For instance, the song 'Highly Exalted' (Israel and Joe Pace) has Israel doing the lead. I really just feed the lyrics to the team and the congregation and the they sing it back.
I'm trying to teach the team to be responsible for their own remembering of lyrics; they're too reliant on me feeding because I feed the congregation.
Lastly, we sing harmony whenever the opportunity presents itself.