Criteria and recommendation letter for GTV

My question arises from this website:
https://technation.io/visa-tech-nation- ... y-criteria

Mandatory:
Show that they have been recognised as a leading talent in the digital technology sector
Question: This requirement looks vague. What can go here as evidence?

Optional:
A proven track record for innovation as a founder or senior executive of a product-led digital technology company or as an employee working on a new digital field or concept-- This is understandable. I work in a product-led digital technology company. I can show my employment letter, latest salary. Anything else that I can show?

Proof of recognition for work beyond the applicant’s occupation that contributes to the advancement of the field- I plan to show mentoring, conference presentation, stackoverflow and paper publication. Any thing else that I can show?

They have made significant technical, commercial or entrepreneurial contributions to the field as a founder, senior executive or employee of a product-led digital technology company- I plan to show 1 granted US patent and 12 other patents applied to US patent office. Any thing else that I can show?

They have demonstrated exceptional ability in the field by academic contributions, through research published or endorsed by an expert- What can I show here?

I know that I have to show evidence to any 2 of the optional criteria, nevertheless, I would like to know what evidence can go for each of the criteria so that I can optimise my evidence.

It is also mandatory to submit 3 recommendation letter from the top tech guys (CTO/founder). I have few questions regarding it:

In which of the above mandatory/optional criteria does this fit in? or is it separate from the mandatory and options requirement

What must be the content of the letter? Any link which can be helpful? Is it necessary that I have worked for them ? Or its sufficient that they are aware about my contribution to the field through some medium (meetup/presentation etc.

Sorry for the long post, but it is much needed clarification.

Thanks in advance