At present, because of the fractional reserve system, the banks could conceivably, on the basis of their enormous excess reserves, inflate their demand deposits by about twenty billion dollars.
If banks instead lend less than the maximum, accumulating excess reserves, then commercial bank money will be "less" than central bank money times the theoretical multiplier.
No, as they can keep the excess reserves firmly locked in the banks' balance sheets by offering a sufficiently attractive interest rate on these deposits.
With quantitative easing, it flooded commercial banks with excess liquidity to promote private lending, leaving them with large stocks of excess reserves and therefore little risk of a liquidity shortage.