The 16' boat is going to have a lot more potential for cruising and you already have a thirteen foot boat, so going for another wouldn't be much of an upgrade. That is not meant as a comparison of the Esky and Eddyline--just the length of the boats. The sixteen footer weighs about 7 lbs. more than the Merlin, so that might be a factor. I assume the Esky is polyethylene, so it probably weighs within a couple of pounds of the 16 foot Eddyline.
No, I don't think the 16' boat would be any problem for you. I would suggest that you give it a very thorough inspection for damage and pay close attention to the seat adjustment device. I would also look for warping, or other irregularities in the hull. Eddyline had a few problems a few years ago with the thermoplastic, but they got it figured out.
You said the boats were at a great price. How much?