Hi Vincent,
Well, Checkstorage may actually work just fine for that purpose. In it's first phase, it uses a number of worker processes to read all the pages in the database (just once per page) to copy the header information into the workspace table in dbccdb. I doubt the SAN cares whether that i/o came from checkstorage or any other read from ASE (but don't know for certain). Checkstorage is actually a good choice for this if it works, as it is designed to minimize concurrency issues with other activity in ASE.
Checkcatalog won't really add anything - it pretty much just reads the system tables, which are small. So you would get some additional i/os on pages belonging to system tables; if the SAN needs multiple i/os on a page to move the page to SSD then that would help - but regular activity on the database is going to be hitting these same system tables often anyway.
I'm not really sure what your second question is asking.
-bret