Why are there no parents?
All able bodied non essential adults have been drafted for the war effort. Leaving a bumble headed mayor, a rhyming sea captain, a grandpa, a stoned snow boarder, and a few essential people left behind (Farmer Umey).
Ryders parents were very wealthy technology barons
Ryders parents left to build advanced technology for the war. Leaving Ryder with the skills, cash, and means to build advanced technology. This is how Ryder can build the pup packs, and why Ryder is always working on his quad.
Ryders parents designed and built the pup patrol
Being leaders in advanced tech, Ryders parents built robotic emergency services dogs to keep Adventure Bay safe, while the real emergency service members are supporting the war. This is why the pups need to be ordered to do the simplest tasks by Ryder "Marshal, use your ladder to get the cat off the roof." This also explains why the pups are the only animals that can talk.
Many of the other animals are beta tests of the pups
Chickoleta was the first, with very limited abilities only slightly more advanced the a biological chicken. Mayor Humdingers cats were the final prototypes. They do not yet have the ability to speak but clearly understand english, and have basic versions of the pups first abilities. RoboDog is Ryders first attempt to replicate his parents robotic success.
Tracker, Everest, Sweetie And Arrby are post PAW patrol prototypes
Created in an effort to eliminate the need for a human master, these 4 show the progress and mistakes in the technology.
Arrby was the first after the PAW patrol. He was a failed experiment in AI ethics. He can operate somewhat independently, however he was designed to bond to a human leader. But they did not give the AI any means of ensuring it bonded with a moral human. He ended up bonding with a rebel militia man who lead Arrby into his pirate ways.
Next was Sweetie, she was designed to bond with a moral human, and intentionally given by her creaters to Royalty in hopes she would learn from them. Sweetie is also quite capable of operating independent of her human masters. However her AI does not yet have the advanced moral guidelines her designers were aiming for. She realizes she is an advanced autonomous being and is striving to gain power over the human race.
Tracker and Everest are more advanced versions, with almost perfected moral codes. However, leary of thier mistakes with Arrby and Sweetie they were both put in sparsely populated regions, to make sure they can't cause much harm to humans if their AI malfunctioned.
Tracker is more advanced than Arrby and Sweetie, but less advanced than Everest. Carlos is there to supervise tracker, not command him like Ryder does.
Everest is the most advanced, not requiring any supervision. That is why she was placed in a area of zero population. Anything more advanced than Everest would be put into service for the war effort.
The merpups are not mermaid pups, they are marine soldiers. They are the final result of Ryders parents experiments. The merpups on only speak in code which Captain Turbit is the only one trained to speak.
The PAW patrol can morph into merpups when the details are uploaded to them via the nose from the soldiers. This tells us the PAW patrol are designed with very advanced nano tech, that is capable of on the fly structural rebuilds. This also explains why Captain Turbit and Ryder are not transformed by the merpups.
The merpups come back to check on Adventure Bay only when certain light conditions allow them to safely leave he battle zone.
Captain Turbit is a former navy code breaker
Captain Turbit can speak multiple languages and can pickup on new languages very quickly. He was a linguist and code breaker for the military before being honorably discharged when PTSD became evident when he spent an entire deployment only speaking in rhyme.
Pups dreams are simulations designed to train the pups
Rubbles many crazy dreams are actually training simulations controlled by Ryder that all the pups experience. This is a great way to train the pups without putting the technology in harms way.
Adventure Bay is protected by some sort of perimeter
No vehicle can enter Adventure Bay. Buses break down, trains crash, trucks break down, even air planes flown by ace pilots crash. This means that no one can enter Adventure Bay without the paw patrols assistance.
Who are they fighting and why?
Dont know yet.