Old manual cameras out of the sky. Which ones to keep?

The value (high to low) is in approximately the order of your list. In purely financial terms, no camera is worth as much as it would cost to get it serviced. Given the term of your deal, I would say keep the Pentax ME, Olympus OM2 and Yashica - perhaps the Petri as a 4th, it's worth very little but it's interestingly quirky. The Eastar may be rare but its value is indicated here:
http://www.ebay.ph/itm/EASTAR-S2-RANGEFINDER-FILM-CAMERA-CASE-/160606336280

Um - the Praktica VLC2 is a hard camera to find. It's also one of the few M42 cameras with interchangeable viewfinders. I would not let it go. In fact if I were to keep only one camera, from a collector's standpoint it'd be this one.

The OM 2 is a good camera with a good lens and worth some money. The Pentax ME is a good camera, not really worth al that much but still a good value. From a user's standpoint I would keep these two.
The Fujicas are a dime a dozen. Good camera though.

Your bottom tier is probably going be the Petri TTL, Yashica TL electro, and Praktica TL3. All three of those are common as dirt, and ho-hum cameras at best.
The Eastar, I see them on ebay all the time for high prices, but I don't think they're worth that much. But it is a less common camera so it might be fun to hang on to.

The VLC2 is a top of the line from Pentacon. If it is working then it is worth keeping. It is a system camera and can do full open metering with electric lenses. sp.

First on the list should be the Olympus, followed by the Praktica. I don't know the chinese camera but certainly would choose this one. Maybe it's not really of any worth, but just for the obscureness factor and that it will receive a CLA makes it interessting. Forth on the list would be the Fujica or the Yashica. The Pentax was also a fine camera, but I'd rather have a mechanical camera than a 70ies electronical. I know that the OM-2 has an electronical shutter, too, but it simply is the better camera.
Just my 2c.

The OM2 would be the one that I would keep above all the rest.

I can't think of a better M42 camera for macro work than a TL Electro X. It and the TL Super are the only readily available screwmount SLRs I'm aware of with a true mirror lockup. Makes the much-lauded Spotmatic look positively ho-hum by comparison. The Fujica may be a dime a dozen these days but is a very capable SLR. To some extent I suppose the answers given will depend on whether people comment on the basis of collecting cameras or using them.

Thanks a million, you've been most helpful! The VLC2 and the EASTAR seem to be woth keeping on basis of their rarity alone, even though initially I considered them as top candidates to go. The OM2 is the best camera of all on paper, but my specimen is in the worst condition of all (wind lever and shutter are stuck, the rubber focus ring hangs a bit loose, there is no hot shoe and there is no case -the only camera without one). Letting it go will sweeten the deal for the repairman too I think. The Pentax is in great shape, even had a film roll in it, I guess it was the last one my unkle used, plus the repairman used to work for the official Pentax dealer here in Greece so it will be easy for him to service. The Fujica is also in very good condition, new light seals and batteries is probably all it needs, plus it's M42 mount (shared with the Prakticas) which is nice in terms of lens availability. It also feels very nice to handle being really compact and all. Keeping the OM would raise the number of different mount types to three which is impractical. The Yashica was my favorite to keep due to nice lens, but it seems to have battery issues and is really big. The Petri and the Super TL3 will have to go. (Maybe I'll switch the Pentacon 1.8 for the Fujinon 2.2 first...). So I'll keep the Pentax and the Fujica on basis of their condition/usability and the VLC2 plus the chinese machine for their rarity. The repairman is an old timer who designed and put into production the first (and only) greek camera called "Picca" (see picture) with imported (german) lenses in the 50s. Like everything else ground-breaking in this country though, it went into oblivion after selling a mere 400 pieces.

"The OM2 is the best camera of all on paper, but my specimen is in the worst condition of all (wind lever and shutter are stuck, the rubber focus ring hangs a bit loose, there is no hot shoe and there is no case -the only camera without one)."
Have you tried resetting the mechanism? To do this depress the small button to the bottom right of the lens mount and turn the shutter speed ring to the reset position. The F1.4 lens would certainly be worth keeping even if the rubber grip is loose. Also the hot shoe was an optional extra on these.

Didn't know such a reset existed. Is it mechanical or battery-dependent? I am out of town for the whole week so I cannot test it right now. Yes, I know about the optional hot shoe, anyway I always try to have my DSLR (a D90) around when flash use is anticipated. As I said in the beginning, these cameras came to me out of the blue, and apart from compacts, my film experience is limited to my father's Yashica 35GS and an old Canonet S both rangefinders quite demanding in their use (at least to an autofocus guy like me), i never owned a film SLR before and I'm only starting to get acquainted with the various types of these cameras. As far as using vs collecting cameras goes, I think a bit of both actually, meaning that the rarity or uniqueness of a camera is always appealing, but I would never keep a non-functioning camera.