Those Active continue to work, especially if deployed.
Their pay is delayed in being received can be anywhere from a few days to weeks which has happened in the past. They have already said that the pay on the 1st will only be a few days of Pay the 16th to the 19th when it shut down. The rest will be paid later.
Most banks/credit unions such as NFCU and USAA are already saying like before they will do an interest free advance on pay just like the last time it happened.
Delays in supplies, non essential civilian personnel not working or getting paid, military academies not having classes because of civilian instructors, child care on base closing, commissaries and exchanges closing, AFN overseas shut down (happened at midnight est already)