Yes, it’s incomplete. The authors got distracted with other things.

Both can be present in the system. Use the SATA drive guide to install it.

There are two sizes! The shorter ones (marked in Orange) go into the Trackpad it’s self

It’s the same issue of getting the egg yolk out of an Egg without breaking the shell. The damage of opening is the issue.

Sadly, not likely! The skill of removing of the display unit and the reattachment determines how water resistant the watch is. Even Apple won’t warranty the watch after a repair they preform either.

This is an iPad Pro not an iPad Air which is different.

Patrick, you were lucky! Likely was a Fusion Drive’d system someone took the SSD out as these often failed as they really can’t handle the constant R/W cycle stress for such a small SSD.

There is no ambient air around the CPU, cooling is strictly handled by the heatsink which thermally pulls the heat away from the chip and then thru a set of fins which air is pushed across by the fan the heat is jettison out of the system via the vent holes. This is how most CPU’s, GPu’s or SoC chips deal with the heat build up.

Technically the chips are Flash aka NAND which is not the correct term for the technology. Unlike a typical M.2 SSD which has a controller chip and some RAM to compete the drive. Apple uses a SoC design where the controller logic is within the SoC chip and the main RAM is likewise used as needed.this design offers better throughput unlike a M.2 SSD as each Flash chip can be accessed independently allowing a pseudo-RAID design which as you add more chips allows a striping of the data across speeding up both the slower write op, but also the read.

@starkoman Steve - The 21” system doesn’t always have the Blade interface populated, only the Fusion Drive or if you ordered the custom build with the blade SSD only option.