There is a lot of misunderstanding of scrum and XP in your examples. None of this is strict scrum.

1. Velocity, stories and story points are not part of scrum, they are part of XP. Read the XP wiki to learn how to do XP properly http://www.extremeprogramming.org/rules/velocity.html

2. Story points are a relative measure of the size of the features and components you are building that is used to forecast and plan. A story point is a measure of the entire teams effort during a sprint including any analysis, planning, design, testing, integration testing and deployment. One story point never equals one day of developer effort or any other fixed measure of time or effort.

3. If you start creating stories for tech lead work and meetings and allocating story points to them then you artificially inflate your teams velocity. The stakeholders and product owner will then expect the team to meet this new velocity in the future. So measuring meetings in story points has no benefit and creates an unnecessary admin burden.

4. A feature is not done until it is fully tested, and ALL known defects are fixed and the feature is deployed to production or a pre-production deployment environment. Any bug fixes are part of the story. The only exception is when you discover a new bug after the story was tested and approved.

5. If you want to dramatically improve your estimating go do affinity or silent estimation https://kenpower.ie/2011/05/22/using-silent-grouping-to-size-user-stories/

https://procognita.com/post/no-time-for-planning-poker-try-silent-sort-estimating-instead-292