Couple of things here:
1. I would not blanketly disable auto update stats. In fact, I would "almost never" disable auto update stats. Its a good idea to update stats as often as you can manually; nightly, weekly, whatever... but there's no benefit to disabling auto stats unless you experience frequent updates that impair performance. Even in that case, you are probably better off leaving auto update on, enabling the asynch option. NOTE: This article is referring to SQL Server 2016 where TF 2371 changes are enabled by default. https://blogs.msdn.microsoft.com/psssql/2016/10/04/default-auto-statistics-update-threshold-change-for-sql-server-2016/
2. TF 4199 should NOT be enabled by default. If the compatibility level of the database is 130, it will enable all optimizer fixes up to RTM. If you need fixes released after RTM, use the database scoped option, not the trace flag.