Those of us who tried it have found varying success: Jason Waddell has written articles on it and I've personally found the archetype to be fun
Straightforward, but not a priority
You can use cards like Land Tax and Tithe to ensure you hit your land drops, and Knight of the White Orchid will put a Plains card from your library into play
There are two versions of packaging you can find for these decks: the full-color box, and a minimal packaging version you can find online
Most Rats are black, but a growing number have a splash of blue since the release of Bloomburrow
In Scarlet & Violet sets, a Double Rare lands roughly 1 in 5 packs, an Illustration Rare around 1 in 12, an Ultra Rare about 1 in 15, and any Special Illustration Rare around 1 in 90 packs