OurHappyEnding

It depends on each couples circumstances, but it would be reasonable to split the costs or for the USC to pay the initial petition fee and the Beneficiary to pay the actual visa fee (both about the same amount) and share the rest of the cost. Of course this also depend on whether you both work and make an income.

Honestly, it is luck of the draw. Unless you get a RFE for missing documents you should be expecting it with the 5 month mark. I know that isn't what you want to hear but USCIS at this stage doesn't do anything special other than to confirm that the USC is eligible to petition for you. USCIS checks background of the USC for criminal record as well as previous petitions and proof they are free to marry.
As long as your petition is not complicated (previous petitions, still married, recent divorce, previous overstays) then you should expect it within 5 months or less. After 5 months you can submit a service request to USCIS and they generally try to work on any backlog as quickly as possible.

Are you the USC or the Beneficiary? So did they return your I-129F to USCIS because the name didn't match your passport or birth certificate? Does your passport have your dad's last name or it only contains the first name?