is it safe to remove soil from basement footing?
The footings need to stay on the originally compacted soil, if possible, surrounded by several feet of soil for support, which is also supported against subsidence.  They have uniformly settled to where they now sit. If you disturb any of them, you may end up replacing all of them and having to jack your posts (if not floors) to get everything back into level, plumb and square (as if).

I have an old (1920s) country house in which the original fieldstone fireplace pedestal was left surrounded by three feet of undisturbed soil, supported with a wall of reinforced concrete, with everything else in the basement excavated 8 feet deep for a new slab and all new footings and posts.

A structural engineer explained why we have to sacrifice those 120 sq ft of basement floorspace "forever".