All you are asking for is part of standard functions in Odoo
2. Activivating serial numbers and you have full tracking of all movements for that serial number. From where got origin, where it was used. And backward and forward.
3. See answer no 2.
4. If you have confirmed the assembly (Manufacturing order), you would need to use 'Unbuild order' and the build it up again in a new order.
5. On the different operations type you set if it is allowed to create new, or only use exiting. https://www.odoo.com/forum/help-1/it-is-possible-to-have-duplicate-serial-numbers-for-a-product-across-warehouses-200345
I have not tested myself, but on that question in the link, they say by default it is not allowed to repeat a serial number.
How do we trace the serial number of a component(e.g. ssd/motherboard) within a manufactured product (desktop) and how do we deal with replacing such a component(if moniter got broken and you have to replace it with a different monitor with unique serial number). Take the ssd, monitor or motherboard as example cases for building a desktop.
I recommend you read the documentation. Set up a test database with the basics apps, Sales, Accounting, Inventory and Manufacturing. Activate use of serial numbers / Lot numbers. Set tracing with serial number on products relevant. And you will see for yourself that the tracking works all the way.
Perhaps this training video will help you understand: https://www.youtube.com/watch?v=-adad86nerA
Regarding replacement and how to, it will depend on if it is a repair after manufacturing is closed for that serial number, a return from customer for repair or if a damage is discovered duriong manufacturing.