Bought 7-8 prints/lithos/etching- found all artists but 2!

I bought a box of smaller framed prints by a variety of artists. Some I could make out the name , some had a bio/coa on the back - but these 2 have me stumped.
And because they were in with known, listed artists, I am hoping someone here would recognize one or both!
Thank you!

PS - 1st has only MC pencil signed, but there is a unusual symbol on the back I think I've seen before, but can not remember where right now!

 

The last one is titled Nuder(?) I think, if that helps anyone.
Another of the other artists in the box was Edna Hibel (a pencil signed, titled Nude III, and numbered - but number is unusual - and since I can't find another example, could this number be one of AP & the edition as a whole?

1st is title of last print - Nuder??



Here is Hibel with unusual number?