Tricolor is a broken harlequin. The harlequin gene takes the typical agouti color banding, and instead of having bands on the same hairshaft, the colors go instead onto different patches of skin. Harlequin is dominant over tortoiseshell & orange, but recessive to steel and the normal extension colors (like black, blue, otter & chestnut).
I have a magpie buck, broken tort buck, broken black doe, black doe, blue otter doe, blue/fawn tricolor doe, broken tort doe, and what I think is called a chestnut doe. Can attached photos if needed.
Magpie is harlequin + chinchilla (which removes the fawn/orange from the coat, leaving dark and pearl patterning). The broken tort buck has the needed broken gene for tricolors, and torts are recessive to harlequin. However, you want to avoid breeding two broken rabbits together, as it may result in 'charlies', rabbits with far too much white, too little color, and possible heath complications with megacolon. So I wouldn't mate the broken tort with the tricolor for that reason.
One reason breeders avoid magpie crossings, is that the chinchilla gene can sometimes cause off eye colors in the kits, disqualifying them from show. But, the magpie buck is a harlequin, and the tricolor is a harlequin, so you should get harlequin kits, and half of them (statistically) should be tricolors, as most tricolors have one dominant broken gene, and one recessive not-broken gene. So, odds are, half of the kits should inherit the broken gene, and be tricolors.
Magpie to the broken tort doe should also produce some harlequins, and perhaps some tricolors as well, as magpie has the needed harlequin gene, and is dominant over tortoiseshell (which also has the desired broken gene.) Depending on what recessives they carry, you could get tris.
The broken black doe is out of a tort, so she probably carries a recessive tort gene. That means that there is a 50/50 chance she will pass along the tort gene to her kits, and a 50/50 chance she will pass along broken. If you breed her to the magpie, who has harlequin, and is dominant over that recessive tort gene, you might get harlequin or tris out of that mating as well. Full color extension (like chestnut & otter & some blacks) is dominant over chinchilla, so mating to the magpie should still result in some full color (non-chinchilla) kits. If you end up with kits with those odd chinchilla blue-gray eyes, or marbled eyes, you can choose not to use those kits in the breeding program, and breed/show the ones that meet the Standard.
When mating a chestnut to harlequin, I often end up with unshowable 'harlequinized' chestnuts. They look chestnut, perhaps a bit more of a rich dark coat than normal, but there will often be faint marbling of colors on the ears or face or lower on the body to betray the presence of the recessive harlequin gene.
My guess would be, that if you are looking to specialize in tricolors, pedigrees are not your main concern. Unpedigreed rabbits can be shown, as long as they meet the requirements in the Standard of Perfection for that breed and color group. Do the mating, keep the best kits, and start their pedigrees with the information you have available. In three generations, you will have created your own pedigreed tricolor line, even starting with unpedigreed stock.
