You have a lot of ingredients and a lot of questions. I can't see anything here that raises a concern in terms of chemical reactivity. Most of the oils are terpene based mixtures. Cinnamon bark will contain aldehyes. Nearly all of these ingredients are used in essential oil therapies, and are mixed on a regular basis. Presumably you will mix this up and dilute it with water before spraying. Probably what you are making is in fact a creepy crawly deterrent, rather than an insecticide. You would probably need to spray directly onto the critter of choice to kill it. I have in the past used an aqueous mix of orange oil, citronella and pure soap as a spray to deter web-building spiders on brickwork around the house. Works wonderfully well, and lasts several weeks between applications. Our dogs, cats, chickens, geese and ducks all lived through it well enough. We just get the pest man in to do the job now, and the animals are still alive.
I'd suggest speaking to your local vet about possible toxicology effects of these ingredients with your animals. Most of the ingredients listed can be toxic to animals if ingested. I know that citronella and citrus based extracts are hazardous to cats and dogs. Cats are especially susceptible and using citrus dog shampoos etc on cats can prove fatal. Garlic is also toxic to dogs and cats; again cats are more sensitive, although the toxicity comes through ingestion. Some types of detergents are dermal irritants for dogs, although pure soaps are ok. Eucalyptus oil, although commonly used as a disinfectant, is toxic to dogs and cats (and horses!) if ingested. Even tobacco can cause fatal nicotine poisoning if ingested. Has that put you off yet? Unless your pets are going to lick the areas you have sprayed, then it is unlikely to cause many problems. But speak to your vet - they will know.
I can't say I know anything about turtles, other than they are a wonderful vector for salmonella. But you probably already know that.