I want to break this individual part into multiple parts and build an assembly with mates so I can simulate motion of the parts.
What is the easiest way to separate this into 5 different sheet metal parts?
Go back through the features and unmerge the merged parts to create the required bodies. Then from the Solid Bodies folder, save the bodies as parts and use the option to Create Assembly. Adjust mates to suit.
Since they look pretty simple part, I would suggest to quickly build them up from scratch via sheet metal and assemble.
You can use use "split" option to break them into multiples bodies and using "convert into sheet metal" option change to sheet metal.
Your tree shows two bodies so some of the features have merged. Unmerge all the parts and then create a config for each part in which you have a body delete feature unsuppressed for each of the other bodies. Then insert this part into an assy as many times as you have bodies, change each to the proper config, and mate away.
Retrieving data ...