Echo what @youarenotkiddingme said.
The train runs through benalmadena every 20 minutes, it's cheap reliable and clean! In one direction it goes to Malaga, in the other it goes to furengorola.
There's a lovely massive park for a dry day, can't remember what it's called but at windmill island (any local person will know it- you'll know it when you see it!) walk 5 minutes up hill from there... beautiful big park with play ground and lots of animals, my niece and nephew same age as your DC loved it there. There's a cafe next to the main playground.
Sea life centre next to the marina.
Tivoli world - check opening times at this time of year .. its a theme park the kids will love
Cable cars up the mountain
Crocodile park (next to aqua land) less than £10 in a taxi from benalmadena
There are loads of Irish bars and many expats there, just ask some people and I'm sure they will advise you of places to go.
Mijas is beautiful but the DC may be bored. Think it's the 112 bus from outside the police station. About a 40 minute ride to get there. Beautiful Spanish at top of mountain.
You'll have a lovely time x