After a Falcon 9 has its static fire several days prior to the actual launch, are the TEA-TEB ignitors inside the engine replenished? Or do they have enough to ignite the engines for the static fire and the actual mission?
Only the in-flight restarts are supplied from onboard TEA-TEB storage. The launch and static fire ignition uses fluids supplied from the ground tanks. There was a problem on the ground supply on the SES-8 launch — the tank was contaminated and the flight computer aborted the launch after detecting non-standard readings during ignition.
Only three engines have the onboard ignitor available on the first stage as others do not restart after launch. There has to be another engine which can start mid-flight — the second stage one (capable of multiple restarts too).