Many of those weapons didnt see action no. Simple because they were prototypes made in few numbers. Well maybe one or another for field testing or some of them for last ditch defensiv arm everybody and defend the fatherland ( volksturm and volkgrenadiers mostly)<3 XD
My ansvers are NOT to be citated as being true because I havent an proffesor title in history or anything. This is only what I have heard and read on various places on the internet and could be completly wrong about everything. But its always something XD
Panzerwurfmine did see action yes. Remember seing an German training film about differant anti tank weapons and it was in it. But it werent so popular because the whole parachute desing of it made it kind of risky because of winds and such :P
Kraummlauf I have no idea if it ever saw battles. But I wouldnt be suprised if it did in small numbers. I heard a rumor that stg44 with just those gizmos were on some elephant tanks for close infantry defensiv from inside the tank. Just twisting it around shooting because the bullet would break because of the odd barrel making it like an auto shotgun lol :P
The mkb42 rifles did see action yes. But not in large numbers.
I am having hard times believing that the Fallschirmjäger bullpup rifle did see action because it was just an prototype. However it looks awesome XD
Volksgewehr 2 and Mg45 I think no. This were made for last defense of Germany but the war was over before they could hit the field.
Walther sturm karbiner 39 I think no. There is only a blue print of it. No actuall picture. PICS OR IT DIDNT HAPPEN :P
The fliegerfaust IMO did see little action in the battle of berlin in 1945. If it was succseful or anything I dont know. I dont even know if they fired it. They probaly used all weapons they could use. But it did particapte in the battle.
Source of this is an photo from the battles of Berlin and you could see one laying on the ground.
(you see it at 2.04)
The deathray pistol. NO XD

My English is kind of useless. But that because Iam swedish Wooohoooj! ;3