It feels a little awkward, when I, as Foxbrow, the ever merry silly gamer, post on other threads and I usually mean it serious.
Anyway, I never really cared about pairings, but names were always interesting for me. Especially for the changes caused by translations (but that is for whole another thread). So I would like to give out some notes about rabbit names in general, based primarily on the book.
1) Plant names
This is an evergreen among rabbits to give themselves names of flowers, fruits, berries and their favorite flyrah. Plant name goes perfectly for any rabbit, no matter if doe or buck. The question is, if rabbits also make difference between the common gender oriented plants or not. Like if there could be a buck named "Rose" and a doe named "Thorn". I personally think it is not impossible, yet I believe such naming would be really rare and (especially the bucks) might be mocked for having such name.
Also, it is natural that the rabbits have to know the plant before using it as their name. So for example, it is very unlikely there will be a rabbit named Coconut on Watership Down, unless a good reason will be given.
2) Nicknames
Rabbits don't really have nicknames in the same meaning we, humans, have. Their nicknames becomes their new real name. The nicknames names only occurs when naming a buck and they are either based on their physical appearance (like Silver and Bigwig) or some of their famous deeds (Bigwig once earned the title Pfefa-rah for beating a cat, also El-ahrairah is a kind of a nickname name too).
3) Lapine names
Well, all the names are actually in Lapine, since it is the language of rabbits. I mean the names, that are kept in the Lapine form, generally for their meaning is more elaborate, to actually translate them from Lapine. The meanings usually refer to some nature phenomen or such alike, but these are not strictly limited to these. Interesting is, that only does have such names (like Hyzenthlay or Thethuthinnang).
4) Local specialities
However, the previous are not strict rules, it is just what seems to me like the common way of naming. It is certain, that every warren would have its own preferences, exceptions or even specialities. Here I am mostly hitting the Darkhaven, where the rabbits are named after the minerals (Granite and Shale). Which not only represents their way of (tough) life, but above all it reflects the surroundings of their warren.
I definitely don't want to ruin your creativity when making new names, but have a look at it as a handy guide - if your new name fits one of these "categories", it is suitable for Watership Down universe for sure.