US Immigration from Colombia

Isi it necessary to provide secondary evidence or with the birth certificate is enough? I only have the birth certificate.

I am currently preparing my package to send, as a result, I have some questions.

I have seen, in my posts, people talking about this field office is faster or that field office is slower. How do you actually check it? (When I use the Case Processing Time tool on USCIS website for I-751, they only have options for service centers or "all field offices")

And I-751 isn't being processed in one of the 5 service centers? It is subsequently transferred to local office? (Because I have seen people talking about the speed for local field office, so I am bit confused)

Thanks a lot