The "check" doesn't matter. You need the minimum perform requirement in the area you are performing.
So if he has trombone skill he can only do his stuff while honking on the trombone. Actually that in and of itself doesn't matter. Almost all of the bardic stuff doesn't really need spoken words to work and the one that does, suggestion only suggests that the bard can make a suggestion to someone he has fascinated, and does not require the suggestion as a part of the performance. There are a number of famous jazz pieces that have a spoken phraise at the end. "Salt Peanuts" and "Pennsylvania Six-Five Thousand" are two prime examples.
"Inspure Heroics" might be a problem. Technically the SRD states, "To inspire heroics, a bard must sing and an ally must hear the bard sing for a full round." So it requires singing, something that's impossible to to while performing with the trombone which is required to get that annoying minimum score in order to acrivate.
So for all the wrong reasons you are generally right.
