Help With ID For 4 Stamps Requested

I'd be most grateful if someone could tell me what these are:

I can help with the first two. The stamps with the "OKCA" are listed in Scott Catalog after Russia under the subtitle "Army of the North". The commentary in the catalog suggests: "The letters OKCA are the initials of Russian words meaning "Special Corps, Army of the North". The stamps were in use from about the end of September to the end of December 1919."

The first one 5k (brown violet) is identified as Scott #1; the second one I believe, would be the 50k (green) Scott #5. At least that's what the catalog says. However, your copy of the 5k looks more blue; and the green one looks as if it says 30k, not 50k, so it may be they are bogus issues of some sort and/or not catalog listed. This area is not my specialty, so maybe others will chime in.

First two : Russia~Northwest

OKCA = Special Corps Northern Army (thanks to 22 crows)

3rd : Lichtenstein...postage due so Bob.
4th : Central Lithuania

Nice gaggle of stamps there :)

Thanks for the help, guys!