Hi Charlie,
Nice promising collection . Did you buy fertilizer ? Time for it ! Rush !
That will help those small things at sky rocketing and developing .
On the hole, just rub clay-dirt to seal the hole and that will do it .
It helps you to know if there is activity in the hole and avoids that water gets in.
If a bee comes to use that hole, just keep sealing the hole, and the bee will go find another hole to use as a nest.