Not knowing the details of those houses I can guess of course in the Case of Tudor not much as they are made by Rolex and often with Rolex parts.
Most importantly, who really cares? it's all marketing really.
As you go deeper and deeper into any in-house you will find that either parts, or materials, or of course equipment are not in-house...in many cases it is also a fallacy to believe in house guarantees any kind of quality. It does not, and in many cases it actually means LESS quality. Why?, because the advantage to sourcing is that you can get the "best" you can get from a specialized maker, rather than the best "YOU" can make. Ig there is a specialist on, for example, Saphire crystal...why would you invest enormous amount of money on development and resources to make your own...which will most likely not be as good?...and this applies to most parts.
Companies like Panera or Cartier are better off using ETA movements than in house movements that may not be as reliable.
Another strategy (Rolex) is to actually buy third party companies and thus making their product "in house" is that accurate? I don't know, the parts are now made exclusively for them but the companies are the same they use to source from.
The most important part of "in house' for me is to have a cohesive in house product design, development and Brand control. THAT is what makes Rolex Rolex, they have full control over their Brand, as opposed to Omega who is part of a larger company, and a public one at that, and bound to commercial agreements and boards of investors that have business rather than brand or watchmaking in mind. Fortunately to date Omega splits their lines between the more commercial, Swatch like, gimmicky and endless LE's and the development of new technologies, movements and higher end pieces (within their segment) So you have 10 versions of the dark side of the moon on one hand, and Bond and Snoopy....and you have the Sedna panda, and the antimagnetic movements etc etc etc
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