Luciano,

what I can tell is: Refreshing an EEPROM is no Problem.

what I can't tell is: what would have happened to the Memory Cells that were supposed to be static if they wouldn't have been refreshed.

I personally wouldn't store "static" data together with "dynamic" data on physically the same chip.
(I wouldn't use an EEPROM for frequently changing data either)
(OK, it all depends on the definition of "frequently")

You could run a simple test to find out where the limits are,
but bear in mind that this test will wear out your EEPROM (sooner or later).

Write some "static" data to some EEPROM locations.
Run un a loop overwriting some other locations with "dynamic" data.
with every cycle of the loop read back the "static" locations and compare them to the initial values.
When the first mistmatch occurs your loop counter will tell you the number of cycles.