Is an F-16 able to fire any of its weapons while on the ground?
Yes, the F-16 can fire on the ground, and it has happened as an accident

A maintenance worker accidentally fired a 20mm Vulcan cannon from an F-16 jet he was working on at Belgium's Florennes Air Force Base earlier this week, destroying another F-16 while damaging another aircraft nearby, according to multiple media reports.
A worker apparently opened fire across the flight line while performing maintenance on Oct. 11, according to Avio News. The F-16 that was racked by cannon fire quickly caught fire and exploded, since it was loaded with fuel and being readied for an afternoon sortie, according to Scramble Magazine.

https://taskandpurpose.com/f16-destroyed-belgium