As a general rule, no.
Not properly
The Glock 22 (full size .40 S&W) and the Glock 17 (full size 9mm Para) have the same external dimensions, and any holster will be interchangeable between the two.
Check the holster maker web sites. Many of their products fit more than one model/make Odin Holsters makes one specific to a Taurus PT111 Millennium Pro
Usually not. The 9mm Parabellum catridge is longer than the .380, as a result, a 9mm magazine is also bigger, and the magazine will not fit in the .380 magazine well.
A 9mm handgun typically uses magazines that hold between 10 to 17 rounds of ammunition, depending on the specific model of the handgun. Some handguns may also have extended magazines available that can hold more rounds.
Yes, it will fit, but the barrel will not go all the way to the bottom of the holster. Depending on the holster, it may or may not make a difference.
9mm and 380 both use bullets with a diameter of .355. However, the cases are a different size. .380 is also known as .380 auto, 9mm Kurtz, 9mm Corto, 9mm short or 9x17. 9mm typically refers to 9x19mm also known as 9mm Parabellum or 9mm Luger. You cannot fire a 9mm Parabellum cartridge from a .380 handgun. The 9mm cartridge will not fit into the chamber of the gun. However, if you were to pull the bullet out of the .380 case and put it into a 9mm Para case the resulting cartridge will work just fine.
Only if the holster was made for that specific configuration or the laser is in the grips.
Many holster makers have one or more types that will fit.
Assuming that a Williams PPK is a copy of a Walther PPK, and assuming that it is marked as .380 caliber or 9mm Kurz, and assuming you mean 9x19mm or 9mm Luger, no. You may get the cartridge to fit, but you should not try to fire it. It may even possibly fire, but will probably damage the gun and possibly the shooter.
NO- outside of case dimensions, the 9x18 uses a .366 bullet designed for the Makarov. The standard international cartridge, 9mm Luger (9x19) uses a .355 bullet. The Luger will not fit in the Makarov, and if you try to fire the Makarov in a standard 9mm gun, you may just damage the gun or blow out the barrel
No.