I don't understand question #1. Maybe you can rephrase?

#2 requires a mix of (i) reference interviews, and (ii) digging into details during candidate interviews. Read these books to learn how:

* Who: https://www.amazon.com/Who-Geoff-Smart/dp/0345504194

* Topgrading: https://www.amazon.com/Topgrading-3rd-Promoting-Turbocharges...

Some additional great resources related to hiring:

How to hire your first engineer - https://blog.ycombinator.com/how-to-hire-your-first-engineer...

Convincing Engineer to join your team and a basic structure for the process - https://blog.ycombinator.com/convincing-engineers-to-join-yo...

General thoughts about hiring - http://blog.samaltman.com/how-to-hire

The book "Who" gives a good idea about a good process. Hard to apply when you are not looking for a "generalist" - https://www.amazon.com/Who-Geoff-Smart/dp/0345504194/

Some of the manager tools podcasts episodes - https://www.manager-tools.com/map-universe/hiring-0

Edit: formatting

The best book on hiring, no doubt, is Who: http://www.amazon.com/Who-The-A-Method-Hiring/dp/0345504194

We used it to build our hiring process for http://www.thinkful.com/ and it consistently proves valuable.

We also use it to help our students prepare for job interviews.