IMHO, your best option is either K-1 or CR-1. You would need to have a legitimate paper trail of supporting documents for that. Receipts from trips such as hotel folio's of your stay, airline tickets if any, passport stamps if you both took a trip abroad, cruise receipts. Photos with family and friends, monetary transactions etc are helpful. Non-concrete evidence such as letters from family/friends etc is no evidence at all.
B-1 would show immigrant intent and is probably not a viable option.
It is now generally taking 5-6 months in many cases. Seems like they are backlogged. If you have a job offer, use that to expedite your EAD card. It would be done over the phone as they no longer do EAD expedites via infopass. If you have a family emergency trip coming, that can be used as a valid reason to expedite using supporting documents.