In a property page, is it possible to show/hide a list attribute if an(other) boolean attribute is true ?
yes that is possible. You can define conditions for property pages in combination with HiddenOn operator to achieve this.
if you run a query select metapropertypage where _Parametrization like "#HiddenOn#" you will find many examples.
the only drawback is that the filter is only applied after the ok/apply button has been pushed by the user. As far as I know there is no _onchange event for attributes which could be used to refresh the propertypage.