I don't think there's really any "rebranding" going on in the case of hares and rabbits. Easter is round about the time when you'll start to see more hares and rabbits outside during the mating season. Hence "mad as a March hare": https://en.wikipedia.org/wiki/Mad_as_a_March_hare
There's probably a long tradition of people in Europe associating March and April with hares, but I don't think there's anything particularly "pagan" about it.
Well, yes and no. It all depends on interpretation. Pagan religions typically had their festivals following the cycle of the year, and spring is naturally when all of nature is working towards reproductive success. The rabbits as mentioned, eggs are still big around easter. Planting of crops, etc. So the symbols are older than the paganism of pre-christian Europe, and probably a whole succession of religions have used the same symbols.
It wouldn't surprise me if the pre-indo-european cultures of the area also had the same symbols for whatever religions they practiced.
The fertility symbols of spring have very little to do with Christianity, and I can't see where they are even made part of the theology. So looking backwards from a thousand years later, it seems like the pagan religions did recognize them as fertility symbols and rites. Even if those symbols have always been there, it feels like the pagans used them to make sense of their world in a way that Christians haven't.
Well, in Western Christianity there were/are the Rogation Days[1] and Ember Days[2] (and extra-liturgical customs that could vary from place to place), certainly related to "making sense of the world" with respect to cycles of nature.
Holy Week (preceding Easter) and Easter itself are full of themes and symbolism, but the focus is different — it's square on the mysteries of the Passion, Death, and Resurrection of Jesus Christ.
See for example the Exsultet[3] and the Victimae paschali laudes[4]
Eggs relate to Easter because it's the end of lent (and you can eat eggs again).
The Easter bunny has about as much to do with Christianity (or pagan religions) as Santa Claus.
So yeah, I'm sure you can loosely trace lots of this stuff back into the distant past. My point was just that this isn't an instance of Christianity taking over or "rebranding" some older pagan tradition.
Eggs can be consumed during Lent (I presume you mean the Catholic tradition of fasting, particularly "no meat", on Fridays during Lent). It's not considered meat.
Among Eastern Christians (Catholics / Orthodox) eggs are traditionally abstained from during all or parts of Lent, it depends on the particular church.
Interesting. That's not the case with US-based Catholics, or other Catholics I've met from Western or Southern Europe and the Americas. But while I know a few Eastern Orthodox folks I haven't really compared the specifics of the traditions.
There's probably a long tradition of people in Europe associating March and April with hares, but I don't think there's anything particularly "pagan" about it.