Impact of Modifying a MultiSelect Field?

I’m sure the ideal is to not make any adjustments to fields after created and listings are populated with them…..

but that isn’t realistic.

Wondering about the more advanced case like a multi select that is created, some listings are populated, and then the multi select is later modified?

E.g.

Let’s assume a checkbox multi select field created as:
Blue, Red, Green, Yellow

Say a listing is created and “Red” and “Green” are selected.

Then the multi select is modified as:
Blue, Orange, Red, Black, White, Green, Yellow

Does that original listing still reflect: “Red” and “Green?”
Or else, like: “Orange” and “Red” (assuming the selection acts as a pointer, still reflecting the 2 and 3 positions)? Impact of adding, editing, removing, rearranging options?

Or something else entirely?

On a sub note to this, what happens within the database in these cases where listings had data populated:
(assuming any field type, but please note if there are any differences in how this would be treated based on field types)

– field is changed to different package
– field is made inactive
– field is removed

Underlying data remain in DB? Dropped from DB? Especially that second question…if field is removed and data remains, is there any way to clean the DB of these artifacts?

Any other quirks to be aware of or things to specifically avoid doing that could break things?

Thanks!

Cheers