The genealogy hobby is all about stick-to-itiveness and being a good detective.Many of the variances you have listed are the results of scibes not recording info accurately or perhaps a family member not understanding a question.
Death records can be bad for misinformation because of the emotional state of the person providing it.For example, my grandfather's death record in 1918 shows his mother as Rosalia Solomka with no birth date or place.If I had stopped there, I would never have been able to trace the family back to 1560 as I have done.Further research revealed his mother's name to be Catherine Steinwand and he was born in the village of Solomka.
It seems you have enough info to make the jump across the pond.The rule of thumb is that the closer you get to an actual event, the more likely the info is to be accurate.I assume that Brzeziny you need is the one a short distance east of Lodz.Catholic records for this parish have been microfilmed and are readily available through local LDS libraries.If you can find Erasmus's birth record, you will have the most original spelling and data (keeping in mind that this info too was written out by a clerk or parish priest who could have made errors).
Michael is not your direct ancestor but his marriage can provide further clues for Mary who is. You have two somewhat consistent locations for Mary - Wyrobli and Wyrobh.These are misspelled but I have found two Wyrobki in Posen which seem to be a good match.You will find one Wryrobki using GOOGLE Maps but that one was only in Posen (South Prussia) prior to 1815.
One Wyrobki was just at the lower end of a lake, 10 km NE of Witkowo and today apparently known as or very close to Raszewo.
The other is only two or 3 km SW of Mogilno.Another km to the west of there is Gozdawa which could be your Gozslava.Seems to me this would be a good place to start that search.
I cannot of course guarantee results but hope I have encouraged you a bit and given some reasonable pointers for carrying on the search.