You rang, m'lord?
Seriously, LOTS of guys know this stuff! But I'll help as best I can:
Bridge: Warpig or ceramic warpig. Depends if you want tight and searing highs brutality or organic with detailed mids brutality. I dont know lundgren but for meshuggah I wouldnt look any further than a C-Pig.
Middle: I dont really know the singles. Perhaps 38th beatle or philking will come along.
But I'll try...
Case 1: not really a single sound, that, but I'd say go for the mid-push of an irish tour or slowhand.
Case 2: It does sound like you want something with or that can be well adapted to an AIII magnet though. Check the range and see if there is one, I dont know. This would provide the jazz sound you seek. SCs arent awefully common in jazz, though, its normally a very hum-bucked tone, so I dont know how much success you'd have with that. You'd probably have to carefully choose a tone control setting with any pickup to tame a singles high end.
Neck:
Case 1: Any number of pickups, as I understand the range. Mule, black dog, emerald, crawler, VHII, riff raff (the obvious one, given the mention of ACDC). Of these I know the crawler and know that it will get that sound very well. There could be better though. Wait for someone with mellower tastes, on average, to come by.
Case 2: By violin or chello I take you to mean an even sound with a pronounced midrange. I'm also assuming that you mean with distortion. That, to me, says cold sweat (again! I always seem to recommend the CS neck! Awesome pickup though). Its got a pronounced mid thats made to shred, but that mid hump (that ex-bkp employee Steve once said sounds 'kind of like a half-c--ked wah') should get you where you want to go.
So you can get youre bridge sound very succesfully, and the neck shouldnt be a problem in either case. But given that you want a very un-single sound from the middle, the best choice there will probably decide which of case one or two you choose. Were I to guess (which I have to, having never made or wanted to make any guitar sound like a violin or chello), case 1 would give you the best results, given that a middy SC with the tone control could do that (probably) but I find it hard to imagine the jazz sounds I know on a middle single. So my advice is something like this:
Bridge: C-Pig
Middle: Irish tour
Neck: Crawler
Lets see what the other guys say.