Can anyone out there help me with any info at all on these Chinese stamps? I have been sorting all morning and these last few are defeating me!

First up is a 1944 Sun Yat-sen with a one line overprint which I cannot find. There is no surcharge, so I guess it is a regional use?

Second one is a total mystery, I must have catalogue-blindness because I can't find it anywhere!

The last little group are all 1945 Sun Yat-sen with what appears to be the gold yuan surcharge, but with an extra line of characters on the top. Again they could be regional.

Any help would be greatly appreciated.

DavidR