UPDATE: Changed wording of several questions to make them more clear. Added two questions.
M'kay, I'm going to try and keep tabs on this, but feel free to leave a message on my talk page if you want to subscribe to this list; I'll update you whenever I add new questions.
Over time, I've come to realize that there are a number of unaddressed background questions about the world of Redwall. For my own amusement and that of the community, I've posted below a list of whatever implied realities or unanswered plot holes I can think of below. If anyone wants to suggest one in a comment, I'll add it to the list and credit you if I think it "works". I'll also strike out any question and credit you if you can provide a definite answer. I'll organize the list into categories later, but for now here's the full thing...
1. Where do the Redwallers - and everyone else, for that matter - get their bread? There is no mention of any wheat fields, mills, etc. - and you'd need all those in place to produce bread in more than token quantities.
1a. And where do they get their cheese from? There aren't any cows in Redwall. (Credit for question goes to Neildown) (ANSWERED: By Brian Jacques, who though ahead and came up with something called "greensap" that can be used as a milk substitute. Though how it makes good-tasting cheese I have no idea.)
2. Who makes all the weapons? Someone must be outfitting and equipping the Redwallers, Hordes, Corsairs etc. - but who? A centralized trading power? On that note, where does the iron and steel come from? Who mines the ore? Who smelts it into usable metal? Who actually crafts the metal?
2a. On a related note, where does all the cutlery come from? ANSWERED (in part): Redwall has a forge in the cellar - at least, it does by the events of Rakkety Tam - and this is presumably where they make their cutlery. Of course, it's still unclear where everyone ELSE gets their cutlery, and where they're getting the metal from... (Credit goes to Gandr Adderbane)
2b. On another related note, how was the Joseph Bell smelted? Yes, Joseph made it, but where'd he get the material?
3. Who builds the ships the corsairs use? You'd need a drydock and shipyard at least to construct the hundreds of ships mentioned in the series - to say nothing of the manual labour involved - and none of that is mentioned in the series.
4. For that matter, who mines all the gold and silver used to make treasure? Who makes the treasure, and why?
5. How does anyone get supplies? Corsairs presumably ship it by boat, but no reference to any major trade routes is made in the series. And surely not EVERYTHING can be made on-site (particularly metallic implements)
6. There doesn't appear to be an economic system of any kind in the world of Redwall - no money and no trade other than the barter system. So what do they trade supplies for?
7. Why would corsairs and searats bother pillaging the high seas when they can't sell their booty for profit to buy weapons, supplies, food, booze, "company" etc.? Without a monetary system, treasure's essentially without value - so why bother trying so hard to get it? Where does the motivation for piracy lie?
8. How does the Redwall Pond still have fish, if there's no river to feed it? Shouldn't such a small body of water been fished to extinction years ago?
9. Where do all the vermin come from? Presumably some of them would just live in the forest (in Redwall, Cluny conscripts some of them into his army), but are there any other major encampments? The Land of Ice and Snow is a good candidate, but not all of the rats could come from there - and that also leaves open the question of where foxes, ferrets etc. originate from. Where do the hordes get their numbers from?
10. Where do searats obtain seaweed grog? A ship is hardly a good place for a brewery. Is there some sort of centralized brewery? (Perhaps that's where the treasure goes...)
11. Why didn't Foxwolf and Silvamord ever manage to produce offspring? Admittedly their mate-ship was a dysfunctional one, but still, you'd think they would have mated at some point or another. Heck; Swartt Sixclaw managed to produce a kid within a year (with the concurrent implied reality that he must have consummated his marriage with Bluefen within a very short period after Bowfleg died). It could in theory be assumed that the world of Redwall has access to contraceptives, but...still.
12. How did Asmodeus manage to produce offspring (Baliss the Slayer is his descendant)? There aren't any other snakes in the are - and snakes tend to mate in large groups, anyway. So how'd he manage to have children? Did he live somewhere else, mate, and then leave for the quarry?
13. Who built Fort Bladegrit? Where did the stone come from? There was no quarry on Terramort, and it's pretty hard to carry stone on a boat, so...
13a. Similiarly, how was Ublaz' Palace constructed?
13b. Or Fort Marshank? ANSWERED: There was a quarry nearby from which stone was mined to build the fort. Credit goes to Gandr Adderbane.
13c. Or Castle Marl?
13d. Or St. Ninian's Church? ANSWERED: In "The Legend of Luke", where the story of the construction is reconted. Credit goes to...well, a lot of people. Let's just credit the Redwall Wiki in general this time.
13e. Or Castle Kotir? ANSWERED: They used the same quarry that was used for Redwall. Credit goes to Brockfang.
13f. Or Loamhedge Abbey? (Credit for question goes to Brockfang)
14. What happened to the Sparra after Mattimeo? By the next book, they've vanished. Did they move away? Was there a plague?
15. Why didn't Asmodeus eat Chickenhound after biting him? Predators kil things to eat them - so why leave Chickenhound lying there and leave? (ANSWERED: Chickenhound was dragged to the quarry for later consumption; he regained consciousness and made his escape. Credit goes to Gendr Adderbane.)
16. Why are there so few pine martens? Just Ashleg and Ublaz, really...why are their numbers so few compared to other vermin?
17. What the heck happened to the Beaver? Was it just visiting from Canada (read: Land of Ice and Snow) or something?
18. Where did Cluny get his horse? They don't appear at any other point in the series - so where did it come from? (Credit for question goes to Long Patrol Girl)
18a. And why would he have a human-proportioned cart, anyway?
19. Throughout the series, no mention is made of provision for sanitation. With medieval toilet and sanitation technologies, how do Redwallers avoid the outbreak of disease, and how do they deal with the sewage everyone produces? You'd think plague would break out in short order without a sewage system in place. On that note, how do galley slaves survive more than a week? Without provision for toilets down there, they should be awash in their own filth and spreading disease to the crew (this happened a lot in real life) - so how is sanitation accomplished? (double credit to Long Patrol Girl and Gabool the Wild for this question)
20. How did Rockbottom survive in the Land of Snow and Ice? Reptiles are cold-blooded, and must keep warm so that they don't freeze to death - so how did Rockbottom avoid dying in such frigid conditions? (credit to Bluestripe the Wild for this question)