The two flags listed as being from Bell's Arkansas regiment are a modified Second National and a flag that is exactly like that of Dobbin's 1st Arkansas Cavalry - blue field with red Latin cross adorned with stars.
The Van Dorn flag on the Iowa site - well they have two actually - and one is from the 43rd Mississippi. I don;t think the other is indentified offhand. Rosecrans claimed 18 flags from Corinth (if I have the figure correct) and most are still not located today.
They have a fine website and are taking great care of their CS flags. I toured the collection 2 years ago.