Bit late to the party and looks like you have potentially come to the end of the road (for now) anyway, but thought I'd comment for anyone else reading this thread in future. Welcome to the world of dealing with the Far East. To pick up on your points about the factory;
- There is the out and liars who will say they are a factory and they are just a sourcing house. A common giveaway for this is when they simply have far too many product lines and/or product lines that completely clash. "Yes, we are a factory, we produce everything ourselves. We make biscuit tins, plastic buckets, tablet computers and wooden picket fencing". Yeah, because they all go hand in hand!
- Then, touching on your experience with seeing various products being assembled, there are the factories that are simply what I call assembly houses. They buy in components, snap/rivet/glue them together and package them. There's a discussion to be had on when an assembly house becomes a factory of course, not everything can be produced in house but for me a factory would be producing key components in house and would have development and testing facilities.
There's not necessarily anything wrong with these assembly houses but you have to then remember that you are at the mercy of
(A) Them deciding to change suppliers of components due to cost/availability/other reasons ending up with a difference specification
(B) Them being supplied (unknowingly to them) with components that are a different spec, changed design, different material etc due to their supplier making a change. This could be due to cost or it could be because that supplier has a different assembly house that has requested a change to the tooling, so they make it for them and everybody else gets the same change whether they like it or not. I have experienced both!
Whether the assembly house is trustworthy enough not to make changes without your consent - well that's impossible to tell until you have a relationship with them, really. And whether they can pick up on changes from their suppliers, that all depends on how good their goods in and QMS procedures are. And generally the better their QMS, the more cost they have, the more you pay. There's a reason you can go on Alibaba and see what appears to be two identical products from two identical factories with one at $1 and another at $2. Price isn't necessarily everything.
And finally, just because you have been given a video tour of a factory or even an in-person tour, that STILL doesn't mean that you are dealing directly with the factory themselves! Factories will often let agents posing as a factory take people round the plant, and they will often even let them put signs up with the so-called factory name on! I.e. if "Xiamen Plastic Manufacturing Co. Ltd" is the actual genuine factory but there is a middle man calling himself a factory under the name of "ABC Manufacturing Xiamen" then they may let him put signs up round the building saying "ABC Manufacturing Xiamen". I have personally been taken to the same factory 3 times, by 3 different people who each claimed that it was definitely their own building, their own factory, and they had their own signage up! Again in terms of giveaways, for this one look for signage that doesn't appear permanent, e.g. it's just a plastic sign hooked onto some chain that could easily be swapped out in seconds. Especially if there is a big main factory sign in Chinese but then the English factory name is on a separate small board on chains, or on a plaque just screwed to the wall.
It's a minefield and without getting out there and/or working with people on the ground out there locally it's very difficult to ever know who you're truly dealing with. There's a lot to be said for working through a 3rd party, MOIC is very well respected on here, my company could possibly help also, we have our China sourcing and QC team, although we are a little different to MOIC. Of course it also depends on what product you're going for - if you're importing 1000 plastic widgets that can't really have much go wrong, and if it does you lose $1000, give it a go through Alibaba. Something like this I would be much more careful about!
