3. On 2.3 Privacy in Bitcoin. You should take not that :
- Few wallet such as Electrum now randomize output order
- Few wallet have multiple change address feature
- Few wallet such as Samourai wallet have advance transaction generation to improve user's privacy. It's called Stonewall
None of these have any impact on privacy if users of Bitcoin are not using these features. When he wrote his paper, transaction fees were >$20, and using multiple change addresses would be very expensive for a business that processes many transactions. The same is true if a business generates transaction inputs in not the most efficient way.
Above all, the most effective way to maximize privacy when using Bitcoin is to abstain from address reuse, and to only conduct business with those who abstain from address reuse. This would be very effective in making "mixers" obsolete, and unnecessary in most cases.