No. I would say not. While historically not all decanters had stoppers, in modern times they are generally expected to and this, IMHO and as Christine suggests, looks to have been designed for a "wired-in cork". In any case not designed for re-use and with a narrowing rim definitely not designed for decanting.
You do not give it and it may be relevant. If oversized it may just be a fun decor item with no intended practical use. If a more modest/ medium size then may have been the container for a (probably) carbonated drink.
Yes but machine blown I would say. Look at the neck.
Looks like the pale green of window glass. Many drinks bottles are re-cycled these days but from window glass ? It can be misleading to read too much into glass colours for identification purposes... so possibly re-cycled.
This is not of the Depression period IMHO but at least 3 decades later if not more.
In UK we tend to use Art Deco, if of that style. If not then "art deco period" or by decade (20s / 30's). In conversation about the period, older people especially may refer to "the depression years" but "depression" is not used in glass or antiques generally as far as I know.