Argon by Tom Anders Watkins

A somewhat similar antiqued effect is found in Captain Kidd

Zweinstein [Dutch] --> Hogwarts [English]

http://i909.photobucket.com/albums/ac297/adonfelker/Potter%20Party%20Mania/House%20Crests/HogwartsGIF.gif
Did anyone make it into a font?

Registered logo may have been developed from a font.
Is there anything closer than Baskerville Italic?

Manual slant

I see that there is no need to modify Avant Garde Gothic.
The modifications have already been done in Abeat by Kai

Logo, perhaps derived from Filmotype Hudson, compressed slightly and sloped

Avant Garde Gothic, customized by clipping _b_, _u_, _d_, _n_, _a_ and editing _t_ makes a match to this logo.

Using Alt letters for _A_, _R_, _T_, _Y_

Yes, a manually compressed and fuzzy image of Onyx would look like this.
Note that the drop/rise on the terminals for _E_ and _T_ match Onyx.

Condensed for lines such as _MILITAIRE_ and _CARRÉMENT_

Gold Ultra Black is not 100% but is close if you use the alternate _E_
https://www.myfonts.com/fonts/fontmesa/gold/ultra-black/glyphs.html#glyphs/512646/513
and the alternate _F_
https://www.myfonts.com/fonts/fontmesa/gold/ultra-black/glyphs.html#glyphs/512646/517

Similar: Bodoni Old Face BQ Bold

Similar: Bodoni Old Fashion URW Bold

Similar: New Bodoni DT ExtraBold

Similar: ITC Fenice with a weight between Bold and Ultra

Appears to be a hand-lettered heavy weight of Bodoni
Closest version of Bodoni that I found is Linotype Gianotten Heavy