For navigating the lore you sometimes need to have the spelling perfect to get a hit. Go ahead and type 'Spearback' into the lore exactly like that and at the top of the page it will have a link to the monster directory. You mentioned Grass Bears and Nightlions though which can only be found in the Riverfall fauna list. If you type Riverfall into the lore and scroll right down to the bottom it will show you the link. I think you'll get a real kick out of the house cats with wings.
The webbing is invisible, which I believe you already know. It's just lines of tightly spun djed and like a spiders web, think of the web Mage as a spider, he knows when someone is touching his handy work.
Dogs and cats are probably the best bet for rats and mice, I would say there is a mix of storage methods depending on how they want to keep the food. The ground works as too does simple tent storage or maybe even trees in summer. They have drying racks, etc. I will check the Drykas lore and see if food needs its own section.
A resin is rubbed into the fabric of the tents that keeps them water tight and protects them from the wind. I'd say there are also a number of types used, but feel like this is mention somewhere. Tents don't last forever and it's safe to say they spend the summer making repairs or replacements when they need to, but for the most part they're hardy and a new one will go a couple of summers without issue.
Of anything I'd say the wind isn't so much an issue as the design of the tents will fight that (for a large pavilion tent, the ones that cost 50gm, think of the Arabian desert people whose tents are large enough to house even their animals. Drykas have whole areas of their tents dedicated to keeping their animals from the weather.
If anything is goin to be an issue I'd say it would be a lot of heavy snow fall. If the Drykas aren't keeping on top of removing the snow from the tops and maybe even sides of the tent they will start to see structure problems.
Yes the Drykas move during the season, just like a farmer moves his cattle to different pastures, the Drykas have to keep their large herds on the move so that they can graze down the tall grass but not stay anywhere long enough that it scars the land to the point where the earth would struggle to recover. If you look at the map of the fall grounds for example, there are two small cities near the coast. They might start camping closer to one at the beginning of the season and end up closer to the season by the end of it. Is would say there are at least two or three shifts that take place; people don't really tend to mention this, some of the smaller pavilions might only make one shot, but for the clans who all own a lot of Zibri and Striders, they need to move to survive and a lot of people follow them for security.
If I missed anything just give me a poke.