I am also interested in the 1812 campaign and if you do some googling on the regiments you are looking for you can find "Napoleon's Imperial Guard Uniforms and Equipment. Volume 1: The Infantry" by Dawson on google books. Lucky enough
chapter 24 Other Regiments are part of the preview. Here the formation decree of both the Velites battalions are listed and that they should have the same uniform and equipment as the fusiliers of the Guard. In "The Napoleonic Sourcebook" by Haythornthwaite it is mentioned that they had the same uniform as the Guard Fusiliers-Grenadiers(not sure if that means anything different than the Fusiliers?). In "Napoleon´s Mercenaries" by Dempsey this is also confirmed and some uniform details are described:
shako
blue jacket with white fringed epaulettes
blue collar
white lapels
red cuffs
white cuff flaps
In this book there is also information on their operational history and they only went as far as Poland in 1812 and did not participate in the march into Russia.
I found no info on the Mediterranian regiment unfortunately...