So I'm relativly new to fantasy and got 2 boxes of KotR and 3 Pegasus knights, but then i decided i wanted something a little more and so decided to go like everyone else to the new VC. However, I still have deep seated feelings for the brets and after reading the fluff from both codeci, decided to wanted to model a hybrid army, have the fluff be as per the Red Duke of Aquitane, and be able to play the army as either a Bretonian army, or a VC army, thus maybe saving some $ and having 2 armys that I really love. Any thoughts? I wasn't going to use a "counts as" army, but rather combine and convert models to fulfil their roles in both armies. Also, i'm trying to stay as close to the identical base size as i possibly can so that the army, whichever it is at the time, is a completely legal one. So far I've come up with these ideas.

Vampires = Damsels and Lords
Men-at-Arms = Skeleton warriors
Peasent Bowmen = Zombies
Trebuchet Operators = Ghouls
KotR or ER = Black Knights
Pegasus Knights = Bat Swarms
Grail Reliquae = Corpse Cart or Black Coach
Grail Knights = Blood Knights

Stuff I don't know what to do for or don't have equivalents in either army

Questing Knights
Dire Wolves
(maybe use Questing Knights as Dire Wolves since they have the same base size, possible mount the knights ON the wolves)
Grave Guard
Fell Bats
Spirit Host
Tomb Banshee
Cairn Wraith
Black Coach or Corpse Cart (Whichever I don't use as a Grail Reliquae)

I was just going to buy the different heros for each army as I want an unmounted, heavy magic casters for the VC, and the heros for the Bretonnians must be mounted. Maybe use the Leon Leoncour model on hippogriff as a vampire on a dragon. The MAA and SW should be a simple enough conversion with swaping parts and a little green stuff. I haven't bought either PB or Zombies yet so idk if i can do the PB without any weapons. Maybe give them a bow in one hand and a zombie weapon in the other.
For the Ghouls, the trebuchet operators it should be just switching them out since neither of them have any weapons. I know that I will need alot more ghouls than I will trebuchet operators, but right now I'm just trying to identify ways I can fill out all the different selections in the armies. KotR or ER could be converted in a similar way to the MAA in swaping pieces and green stuffing parts for the Black Knights. For the bat swarms I was thinking of pinning bats to the Pegasus knights so they would be Pegasus Knights with a swarm of bats around them. I don't really know what to do for the reliquae whether its base matches a CC or a BC more, but whatever is more similar basewise i'll probably do. Also, as I write this, I feel that I could probably use Ghouls as Battle Pilgrims also to fill out the spaces that the battle pilgrims fill out. Finally for the Grail/Blood Knights, I haven't gotten a box of Grail Knights yet, but I think combined those two sets would look truly awesome.

I know that this should probably be in the modeling section but I also want feedback on this army fluffwise and any gaming input as I am new to fantasy still. Like how well does a mixed Brettonian army work as compared to an all calvalry or mostly calvalry, and how effective or fun is a magic heavy res VC list? Also, how would they fare as a single army together?

P.S. this is going to both Brettonian and Vampire Count forums.