I have two digest-sized Yaffa issues of Marvel's Greatest Comics! featuring Fantastic Four - #'s 3 and 4:
These issues reprint the covers and story contents of Marvel's Greatest Comics #'s 30 and 31 - two Fantastic Four features plus the Human Torch and Thing backups, with the odd page omitted eg. the splash page for Defeated by the Frightful Four! in #3.
I don't know if there were any subsequent issues in this series.
There is a Marvel's Greatest Comics! #2:
Based on the cover I don't think it's related to #'s 3 and 4 in the way one might expect. The cover is clearly a Yaffa contrivance, and doesn't appear to contain Fantastic Four reprints as per the preceding U.S issues of the series - but I note that the Marvel's Greatest Comics! issues published before #30 did feature Dr Strange stories, so maybe it is loosely related after all.
I don't have information on a Yaffa Marvel's Greatest Comics! #1, but I have a suspicion #2 is a reprint of #1.
Or I may be thinking of Marvel Tales #1, which has a similar montage featuring Dr Strange and The Hulk, and which I can confirm was reprinted as the second issue in the series:
Update: I can confirm Marvel's Greatest Comics! #2 ($0.60) is a reprint of Marvel's Greatest Comics! #1 ($0.50).