Only a very experienced lily hobbyist would be able to visually verify or identify to an extent what is what once they become intermingled. Leaf color and charactur is only one clue. The color and charactur of the bulb and stem are two more. Rate of multiplication is another.

It's important to note there are 9 major divisions (families) of lilium. The most common ones are Asiatics, Orientals, and Trumpets. Most all commercially available lilies today are hybrids of these. You have two types, Asiatics (Trebbiano, Centerfold and the orange one) and Orientals (Casa Blanca and Stargazer).

Asiatics multiply much faster than Orientals. And their bulbs are different color and texture/appearance/size, etc. So, in your situation, it is poissible to seperate them into two groups: Asiatic and Oriental. You will have many more Asiatic than Oriental bulbs. Then once those are seperated, you can further try to seperate them into smaller subgroups by bulb color and texture. In this manner, you may be able to seperate all five you have mentioned but you still won't be able to tell them by name until they have grown substantially in height or near budding stage.

The Fall (October) is the best time to seperate/transplant lilies.

Interspecific, Thank You. I've got lilly hell! I think I'm going to have a roadside giveaway. I'm pretty sure most of them are the orange one whose picture I've posted above. I had no idea they would multiply so fast and heavy. However, I adore them when they bloom!