SSN related – Walkin?

Hi, I just relocated from India to Seattle (Redmond) and I got ssn appointment on Dec 26th in Seattle and my dependent got it on Dec 8th in Seattle.

1. Can we go walk-in to either of Bellevue or Seattle offices to get it sorted quicker than appointment dates?
2. Is it okay if my dependent has an earlier slot than mine?
3. I see better availability at Everett office. Is it okay to find a slot there? My relocation partner is advising otherwise due to potential delays and unwanted issues. Is that true?

Thanks in advance