You are going to have the best time ever because I am guessing there will be two hundred singles from the Hosted Singles from Vacations to GO group. That group will be on that ship for Halloween.
Ask the Matri Di on the first day to put in a late dinning table near the Singles group. That is what I did one time and I got to meet some of the singles.
Some of them like to hang out at the bars.
On the first day and maybe second day they will all be wearing blue t-shirts and a name tag in a container on a lanyard.
Just ask the persons you want to meet who they are and where they are from and you will be able to get to know them better.
They will also be wearing a blue wrist band. Maybe the color has changed.
You will not be able to participate in their activities but you will be free to mingle with them around the ship.
In the mornings they like to eat at the buffet til 10 a.m.
Some of them will be signing up for the ship tours so you will get to meet some of them.
I will be cruising on the Carnival Splendor for Halloween and there will be a different singles group on my cruise.
I think most all the ships will have singles on the ships for Halloween.
Anyway, you will be having lots of fun because it will be a Halloween cruise and the Mariner is perfect for a Halloween cruise. Have lots of fun.