Laelia harpophylla (Caliman x Sandra) - Need help with the nomenclature
 

I'm not really sure what is the (Caliman x Sandra).
I know there's an orchid vendor in Brasil called Caliman.
Is this related somehow?

I'm guessing that Caliman and Sandra are the cultivar names of the parents and should have been written as ('Caliman' x 'Sandra').

If the name Caliman has its origin from the vendor I've mentioned, it means that it's a cross between two varieties propagated by Caliman vendor and Sandra (whatever it is, a vendor, an orchid enthusiast, etc)?

A cultivar name doesn't have to be the grower... there is no standard or registration for a cultivar, unless it is awarded. So it is just two L. harpophylla cultivars, that the grower (or growers) felt were distinctive enough to name. The name would correctly be L. harpophylla ('Caliman' x 'Sandra')