I never got a guide or charter when I was down there but did find fish at Isla Mujuieres, which means the Island of Women. I saw some women but it was more cancun's dumping ground when I was there. If your at the hotel strip you can hop the ferry and head over to the island. If your at a resort or hotel they may have free coupons for the ferry with buffet on the island.
The opposite side of the ferry landing is where I did my fishing. It kinda looks like the rocky shoreline at Brenton Point. I would swear Stripers would be there.

It's best if you rent a scooter or bicycle to access the back shoreline. It's a bit of a walk. I was there alone and felt pretty safe, never had any issues. The only shady area was on the North side of the island with huts, away from the tourists. I think that last hurricane wiped out those stick houses.
I found Snappers and Snook when I was there, all were under 10lbs. 40-50lb flouro leader is needed to land those snook. Razor sharp gill plates will cut through the leader. It wouldn't hurt to bring 14lb-20lb leader in case other types of fish get line shy. Crystal clear water there. You can fish from the rocks and hop. I wouldn't recommend wading there, you never know what can be lurking in waist deep water or worse what you can step on.
I used Spooks, Jumping Minnow, DOA Shrimp in Rootbeer, and 3" Storm Mullet's with the red eyes. St. Croix Tidemaster 3 piece 1/2 to 2oz with Stradic 5000 and 20lb Power Pro.
Show us some fish porn when you get back.