Lanzarote has some great trekking and the Timanfaya National Park is stunning!! Papagayo is a cracking (partly nudist) beach and there is much much much more to the island than the 'fun pubs' and fry-up joints of Playa Del Carmen.
It's relatively inexpensive and has a character that is unique and the best thing is that if you hire a car and go exploring you will see some cracking scenery, meet some great people and definitely get a tan. The temp will be late 20's if not hovering around 30 in March!!
I agree that Morocco will be a bit chilly still in Feb/March. Essaouira is a cool beach area but very windy (one of the best lpaces to kite surf and wind surf in that part of the world) so best visited in early summer really.
Agadir is a bit grotty at any time of the year and the beaches in Lanzarote are far better.
I would also love to go to Cape Verde and it has become cheaper to visit in the last year or so. That would be a cool place to go!!
Wherever you plump for have fun 