We go to Sourh beach often and sometimes fly in and out of Ft Lauderdale. We've always grabbed a cab and had no issues.
Some cabs are minivans so they can accommodate your group.
Are you looking for a limo service?
Catching a cab has never been an issue. Daughter and I are going back in March and will do the same.
Last year a cab from Ft Lauderdale to south beach was less than $100 with tip. Straight shot to hotel no stops.
You could use super shuttle but then you're at the mercy of how many stops before yours.
What hotel? LOVE the Loews at north Miami beach!!
ETA; that hotel cab fare will be much less since its at Ft Lauderdale. Have you been there? We've stayed there and loved it although it's been several years. Enjoy yourselves. I forgot the name of the restaurant but there's a cool restaurant with swinging tables (gliders) that's fun and good people watching. The spa at the marriott was very nice as well when u was there. Enjoy!!!