Yes, there is no synchronicity because since the beginning the books (which were 48 pages) had backup features related to the FFs: Strange Tales, Dr. Doom, Sub-Mariner, etc. and when they ran out of FF material they just used the Marvel Two-In-One stories as FF stories.
The graphic design was averagely pretty good. When they started, since they started in 1971, they used the "fatter" FF logo and redesigned it as a Fantastici Quattro logo, starting from #1, so the original logo, properly speaking, has never been used here:
When they reprinted the classic stories, they launched a new title "Fantastici Quattro Gigante", magazine size, which reprinted chronologically all the FF and Strange Tales stories of the Torch and the Thing. The colors of this multi lettered large logo were sometimes pretty "psychedelic". This is my favorite italian edition, and the one I have in full (but it stops at FF#84):