Can small batch and low-volume manufacturing be manufactured in China?

The honest answer to "can I manufacture 100 units in China" is yes, but not by the process you were picturing. Small runs work when the process has low fixed cost — machining, silicone, sewing, simple assembly — and fail when it does not, because at low volume the set-up cost is spread over too few units. The correct move is usually to change the process for the first run and change it back when volume arrives. In practice the answer is almost always yes for a lawful physical product, and the useful question is which process and at what volume. For this category: As low as 1 for machining, 3D printing and hand assembly. 50–200 for silicone and cut-and-sew. 300–1,000 where a printed plate or a simple tool is involved. 1,000+ for injection moulding and die casting, because those tools are the expensive kind. The whole point of small-batch is avoiding a hard tool. Soft tooling — silicone moulds, urethane casting, printed jigs — costs USD 100–800 and may last a few hundred parts, which is often enough to validate demand.