no. You only retain skills that are available for Alphas, the rest get locked when you revert.
As an alternative you can set up your sale orders at citadels with market service. That way Broker fee will be only what owner has set (it is also unaffected by skills and standings). For example, near Jita such a citadel can be found in Perimeter - only 1 jump away.
Shameless self plug:
Imo, restricting market PvP ability of alphas might negatively affect ISK velocity (market activity) which is bad for the game.