Only include what is asked on the 129f form. Beneficiary passport not required. It only asks for last visit to USA and if applicable the details of entry if currently in USA. Text messages are weak evidence
I was there in mid January and I didn't feel uncomfortable with the airport. I was in t3. Like anywhere else just keep your wits about you and you should not have any trouble.
Also k1 provides a limited time (90 days) to see if you really want to be together without any commitment. If for some reason the relationship doesn't work out then separate and no need to go through divorce process. The non us citizen must promptly leave to avoid any over stay.
Petition expires 4 months after approval. But if you have difficulty scheduling interviews and medical a note to the embassy would help. Once you have case number from the nvc you can schedule the medical and interview. Get cracking