I believe that players who have not yet been spawned are frozen hang around at 0,0,0 so your thought would be correct.
Regarding the second question: Did you use setCameraInterior?
Moved to correct section. Please post at the appropriate place next time.
Concerning your problem i suggest you to try the latest nightly build which is available here https://nightly.multitheftauto.com
Just install it on top of your current MTA installation.
What probably causes this is the vehicle interpolation. It makes sure that vehicles are moving smoothly so they won't stutter at high speeds like in MTA:Race. Unfortunetly this only works by delaying every remote Players vehicle by a few hundred ms which add upon the usual ping.
A solution for that would be to also add some kind of extrapolation where the position of remote vehicles gets predectid like in GTA4-MP. This may cause some other desync issues though.
What probably makes MTA's sync so good (but not perferct) is the lag compensation. Whenever a remote player shoots your local player will get moved back to the position where he was when that player shot to compensate the time delay between sending and receiving of the shoot packet. This isn't really noticable in-game except from blood particles spawning somewhere off your player when getting hit.
The first argument of math.random is the lower and the second the upper limit for the number to be generated.
In your case the lower limit is greater than the upper which makes no sense and thus gives you an error.
I think moving back would be a good decision. Sure that fork system makes it quite easy for patch contributers to get their changes applied and reviewed but it shouldn't be that difficult to get this working in a similar way with SVN.
As already mentioned a major downside of GIT is it's complexity. It's just way too easy to break your local repository and usually I had to delete and re-clone my complete fork in order to fix it up again. Seeing your patch lying around in the bugtracker for weeks is less frustrating than dealing with GIT in my opinion.
The "Sync error" bug used to appear in earlier versions and should be fixed if the server is running the latest one (1.0.3)
Network trouble and a following disconnect from the server usually happens when the server crashed but can also be caused by general connectivity problems.
The dofile function is disabled in MTA.
All scripts in one resource are in the same luaVM so you can just do normal function calls across the different script files.