Front House Posts Not Resting on Anything
What you need to do is get a couple of hours of a residential truss engineers time.

Ask him if the posts are designed, or should be structural load bearing components of the frame, or just look pretty?

If they are supposed to hold up your house, below frost line footings and fiberglass posts are in your future.

If they are just to be pretty, then shims and hydraulic cement are all you need, and then replace with fiberglass pieces as time and money allow.

Fiberglass posts, columns are great, lightweight, any shape you want, load bearing or not, stay straight, no rot, no bugs, take paint so well.