My family all live there. This is the order id do stuff in:
The zoo & play barn at the zoo;
Stanley Park (is fab, even in winter, go to the pricey 1930s building cafe for lunch, wander all over but esp the huge play area);
Blackpool tower circus and jungle jims plus dino crazy golf (not been to the rest of the tower id give it a miss based on age of your dc and these are best bits). Circus is a must even for 2yo. Its long. Book ahead for tower stuff. and get discounts if you can;
Sandcastle water park;
Get the number 14 bus to farmer parrs for the halloween activity go dressed in costume OR get the tram if you prefer, get off at Rossall lane walk all the way down rossall lane cross the main road and farmer parrs is at the other end of that lane.
Go to bispham as it gets dark, park blackpool side of the town 'centre' and walk from beginning of tableaux to redbank road. Then go to Bispham kitchen for fish and chips. Or ride from starr gate (or somewhere around pleasure beach i.e start of the lights) to bispham (end of the lights) on one of the lit up trams, or any tram really.
Cant remember the name but there is an excellent Blackpool institution ice cream shop south shore way.
The prom esp outside blackpool tower and down to the beach to pick up stones / dig if its not raining.
Theres a sea life centre (im not a fan, never been)
Think theres kiddie rides up near pleasure beach nicolodeon?