I will dig thru my bookmarks for info, but I can easily explain why your black and albino gave you brown.
First there are 2 main kinds of hair color patterns: hairs that are the same consistent color from tip to end, and hairs that are banded in colors. That is controlled by one gene, the Agouti gene. It is abbreviated as A for the dominant (banded) version, and a for the recessive non-banded version. Each rabbit has 2 copies of each allele (one from mom, one from dad), so the options are AA, Aa, or aa. The aa version will always show as a non-banded hair, the AA and Aa will always show as a banded hair. Wild rabbits and your brown babies are both showing an agouti or banded type hair, but it seems to have a lot of names in purebred rabbit circles, castor, marten, etc. A solid black rabbit is always aa, or non-banded.
An albino rabbit is a joker and the joker is wild--I will get to that in a minute.
There are two main pigments in rabbits, red and black. All the colors we see are combinations of (or lack of) those two. The gene for black is usually coded as B (dominant and black) or b (recessive and...not black... usually expressed as chocolate brown--not the color your babies are). Your black rabbit must therefor be aa BB or aa Bb, but given that dad's ancestors are black or some kind of black variation going back 5 generations, we can assume for the sake of simplicity that he is aa BB.
The color factors for red are slightly more complicated, but in this case we don't really have to go into that.
Finally let's get back to albino. I said it is like a Joker, but in a way it is also like an ace. It is both the high and the low card depending on how you look at it.
My metaphore is breaking down, so I will just get to the third gene we need to talk about--the "Color" gene, which is coded as C for dominant, full color expression, and c for recessive, albino. This is also a gene that controls both the chinchilla coat pattern and the "pointed" pattern of a Californian, but we are going to ignore that for now.
CC or Cc would be a rabbit expressing all the color it's OTHER genes dictate, and cc would be a rabbit expressing NONE of the colors its other genes have. This is like an on/off switch, and if it is off, it does not matter what complicated genes the rest of the colors have, the rabbit will be albino, or a red eyed white.
So this is what I assume.
Your black rabbit is aa (non-banded) BB (black) and CC (all colors showing).
Your albino is only showing us cc (albino) so would be ?? ?? for the other two genes.
Your brown babies are A? (showing banded) B? (showing black) C? (showing color), meaning anything can be in the second position and you still get the wild brown rabbit color.
Given mom and dad though, we can fill in the gap for two of those. They have to be Aa (banded, but carrying non-banded from dad) and Cc (showing color, but carrying albino from mom). We do not know what mom's Black gene is, so they remain B?.
In a feat of reverse engineering, we can also know now that mom has to have at least one copy of A, or you could not have gotten wild agouti colored babies, because dad could not have contributed that. So her genotype is A? ?? cc.
