If you use the first ability of Bard's Company to cast it as though it had flash, you must control a Human only as you begin the casting process and put Bard's Company on the stack. Losing control of that Human while you're casting Bard's Company (perhaps because of sacrificing it to activate a mana ability) or in response to Bard's Company won't affect Bard's Company on the stack.

Once a spell or ability that causes you to recruit begins to resolve, no player may take any other actions until it's done. Any responses made to the spell or ability must be made before you draw, discard, and potentially create a token.