Well, line-bred traits are hard to predict, you can get hatchlings from the same clutch where one has the trait strongly and the other has none. Generally you will need to breed the best examples of that trait to each other (preferably from different blood lines) to increase the strength of that trait in your gene pool and increase your chances of producing great examples of it.
As for the other combinations you asked about, here's how it would go:
(1) LINE-BRED to RECESSIVE: If the parent is homozygous for the recessive trait (e.g., they are albino) then the offspring will be 100% het for the recessive trait (meaning they will not express it, they will just carry one copy of the gene). If the parent is itself het, then there is a 50% the babies will be het, although there will be no way to tell which are and which aren't. They may or may not have characteristics of the line-bred trait.
(2) DOMINANT to LINE-BRED: If the parent is het for the dominant trait, there's a 50% chance of the offspring inheriting the dominant gene; if they are homozygous the offspring will all inherit it. Since a dominant gene is always fully expressed whether the animal has one copy or two, you can immediately see which offspring carry it and which don't. (What "dominant" trait are you asking about?) They may or may not have some characteristics of the line-bred trait.
(3) CO-DOM to DOM: The dominant trait will behave as described above. If the parent is het for the co-dom trait, the trait will be "lightly" expressed in the parent, and in the 50% of the offspring who inherit that one copy. If the parent is homozygous for the trait (a "super" whatever), 100% of the offspring will inherit one copy and will also "lightly" express the trait. For example, a giant bred to a normal will gve you about 50% giants, whereas a supergiant (homozygous for the trait) will give you 100% giants. With a co-dom trait you can only get the full expression of the trait (supersnow, supergiant, supertangerine) if both parents carry the gene and the offspring inherits a copy from each parent.
(4) LINE-BRED to RECESSIVE to LINE-BRED: Assuming you are referring to an animal that is homozygous for the recessive trait (like an albino), the first breeding would give you hets for the recessive trait which may or may not express the line-bred trait. Breeding one of those hets to another animal that carries the line-bred trait you want will increase your chances of getting that trait (assuming this is the same trait you bred for originally, not a second unrelated trait), but the offspring will not express the recessive trait unless you breed your hets to other animals who also carry the recessive trait (e.g., breed the albino hets to other albinos/albino hets who also carry the line-bred trait you are interested in).
If you want more details and/or percentages for specific breedings of your animals, post the possible pairings (be sure to note if the parents are homozygous or het for any given trait) and we can give you more specific answers.
PS: Although the term "het" is most often used with reference to recessive genes, where the trait is not "visible" in the animal, heterozygous just means carrying one copy of the gene. An animal can be het for a co-dom or dominant gene as well. Co-dom hets are obvious, since the trait is expressed differently in hets and homozygous animals, and breeders generally use the term "super" to refer to a leo who is homozygous for a co-dom trait.
