I would be looking to loan the likes of Johnson, Carruthers, Williams, Devine, Siegrist, Burke, Donacien etc. It's nice to keep the group together and so on but the best education they'll get is in meaningful action.
From what I can observe and from what I've learned, the quality is improving down the age groups so these players in their late teens need to be ready to push for a first team squad place or they'll be caught by those behind them.