I will try to answer your questions:
1 – In this case you probably mean internal devices. You may want to check the following lists:
- Intel® NUC Boards and Kits — Tested Peripherals
- Intel® NUC Boards and Kits — Customer-Reported Peripherals
2 – The PCI Latency Timer limits the time in clock cycles that a PCI device can hold the PCI bus. Only applies to conventional PCI devices.
There is a good explanation here: http://www.techarp.com/showfreebog.aspx?lang=0&bogno=138
3 – We only suggest using default values for the performance settings. You may be able to change some settings based on the Intel® NUC BIOS Glossary document you linked above or according to the information publicly available on other internet sites. Keep in mind that overclocking may have an impact in system stability; it can result in data corruption, increased temperatures and unreliable system behavior. It will shorten the life of your product and voids the warranty of your processor.
4 – The Performance Tuning Protection Plan is available mostly for unlocked retail Intel® Core processors. For more information please go to the FAQ section: http://click.intel.com/tuningplan/faq
5 – You can search on the internet for what other users have to say in regards of their experience with different settings. Hopefully other community members will express themselves here. I suggest you always keep in mind the message explained in point 3.
6 / 7 – I believe this is explained above. Do not hesitate to ask if something was not covered or if it needs more detailed explanation.
8 – The Intel® processor is set to high performance while it will still take advantage of power saving features.