Little Details

My fictional world is based on a critical point that happened in the past: Magic, which beforehand had been used in everything, suddenly stopped working. Up to this point my world had been a sci-fi/technology-advanced world. Magic suddenly stops working, and everything breaks. Thus technology-wise the world is thrown back to non-magical means (which I envision as being the typical medieval fantasy world), though the knowledge of having more advanced stuff still exists (though probably a lot of it was lost, since if it was stored in something that used magic -- and everything pretty much did -- it crashed).

1. How long would it take to reinvent modern technology using a different power source?
   
   I'm hoping for a few centuries, considering our own history (medieval to the 2000s), but this was when we didn't know what was possible. For a very stretched example, it's like as if electricity and combustion in our world suddenly stopped working, but photosynthesis still did, and some guy wants to recreate the iPhone using photosynthesis. XP
   
   I really have no idea how to search this, since it's more theoretical. I tried "information technology history", "invention history" and permutations of that but that gave, well, history, and it doesn't really fit what's happening in my fictional universe.


2. Can denim be manufactured by hand, or by very simple machinery?
   
   I keep envisioning my main character in loose jeans for some reason. Because of the aforementioned magical crash, the previous methods of manufacturing don't work anymore -- so I'm trying to figure out how the cloth can be made by hand, or the simplest machinery that will do it feasibly.
   
   Search terms: denim, denim manufacturing made by hand textile, "how is denim made", "cotton twill textile hand" <-- I learned about the weave, and stuff on how jeans are hand-made, but not on how/if the cloth itself is made by hand...

Time: modernish
Place: doesn't really matter, it's futuristic, although I use a mixture of Aus/USA/UK elements

I am looking for some idea of police numbers in a city of approx 20,000 people, based on real world examples. And how many stations/points of presences/depots they might have, how many specialists, what sort of support staff and similar statistics. Especially the support staff.

(EDIT: one station seems to the norm, thanks)

I've googled on various combinations of police force/precinct/station and size/structure, but there is such a bulk of related information out there and I can't think of any "specific" words so I could spend week son this and still not find what I want.

So, I have a planet of human/animal hybrids who originated on Earth. They were genetically engineered to be soldiers/slaves but were freed and, with the help of pure human comrades, made it to the planet to be free from human tyranny. I'm trying to get a background on their race and the different kinds of chimeras there will be on the planet. Does anyone know which animals would have the most chance of being successfully cross-bred genetically w/humans?

I've tried searching using, "chimeras", "parahumans", and "animal human hybrids" on Google and Wikipedia but the info I find is more about the ethical side of things, which is interesting but not what I am looking for, and doesn't really go into details that I need. Any help would be appreciated. Thanks!