Canaries are the only place short haul guaranteed to be above 20c. You can get there pretty cheap. It's around 24-27c every day but feels hotter in the sun.
We've been here a few times www.booking.com/Share-VcjsRz Nice low-key resort, the apartments are spread out well and the villas are great. Downsides - the hotel restaurant is OK for kids but nothing special for grown ups (but we're a bit fussy/foodie) and you need a car/taxi to get to the resort and beaches.
Depends on what you mean by nice! Do you mean naice, nice or ok and cheap? What's your budget?
We've been to Fuengirola/Los Boliches and Benalmadena/Arroyo de Miel areas. I wouldn't go to either in August, but both are fine in low season. Good beaches, range of restaurants, good public transport etc.
Easter weekend is incredibly busy with Easter celebrations in Malaga city. Shops shut on Sunday, but restaurants are open.