E. casseliflavus and E. gallinarum can show motility in some cases. All other enterococci are not motile, especially not the most common species faecalis and faecium. Work in more recent times has been published in Russian or the exact species has not been identified. Considering that Bergey states that they may have flagella, and since this is the usual form of bacterial motility, it is safe to say that some isolates of E. gallinarum or E. casseliflavus can have flagella. Yes, but not very often.
Most studies look only at antibiotic resistance.
There are only very few virulence factors known for the major players, E. faecalis and E. faecium. In general, the bacteria are very resistant to harsh environments and they inhabit many different ecological niches, including humans. Endocarditis , endo- inside. Chronically over time localized inflammatory reaction causes the heart valves to become hardened or stenotic and they may not be able to function effectively. Due to the fluid dynamics involved in blood flow through the heart, white blood cells cannot adhere to the heart valve surfaces because of their large size.