Combat Engineers - Very Weak
Eastern Front Sappers - Similar yes, but not identical
Marder II - Can't say its in the game anywhere
Panzer Infantry - Elite Inf, not really similar to Storms
FlaK pit - more like a single barrel FlaKveirling in a mortar pit
Panzerwerfer looks nothing like a Walking Stuka, look it up, completely different
The last two yes, I admit to taking because I couldn't think of anything worth putting in there...
But I am talking about your concept as a whole would make me feel like I am playing Blitz not a new faction