1. It depends on the expired database. Expired data remains viewable on certain databases like nav data and terrain. Chart data and safe taxi are viewable for a certain amount of time after expiration, but after this time period (a couple of weeks I believe) the charts are no longer viewable.
2. User defined holds are programmable on the latest software version (don't know the number). The revision came out with the new G1000 equipped Seneca V and is supposed to be available for any G1000 installation soon.