Yes its not a leaf, its new growth 'Keiki'. Vanda type orchids open side branch and produce new growths, regardless or if the main growing tip is damaged or not.
As for how long, most Holcoglossum leaf have to be at least around 12" range before the plant will flower. Although this is related to Vanda, you to provide much cooler growing condition than most Vandas. Cooler dryier winter around 10-12'C is need for good blooming for these guy.