How about creating a centrepiece unit? The unit I'm thinking of is a bit like this one:

The central palanquin could be carried by the 4 unarmed mummies. You would then need to make or buy a palanquin and convert from your spare figures or buy a suitable commander/priest/priestess/sorcerer/sorceress figure to sit or stand on it.
The soldiers can be conversions of the figures you have in the picture. Ending up either as sword and shield or spear and shield armed. Weapons and shields can either be bought or home made in Ancient Egyptian style.
The left over figures then become beastmasters. Add collars from green stuff or similar to the scorpions. Attach thin chains or ropes (thread soaked in thin PVA) to the beastmasters. Though I might be tempted to leave them separate and create a new "sub-unit" of a few beastmasters who walk in front of the Palanquin unit and as it approaches the enemy releases the scorpions which disrupt the enemy formation just as the unit charges home.
Alternatively the scorpions become decorations on the palanquin.