Aerobic respiration and photosynthesis were developed internally rather than resulting from endosymbiosis of chloroplasts and mitochondria (or rather equivalents to the same).
Invertebrates are divided into soft-bodied invertebrates, like worms and mollusks, and hard-bodied invertebrates, like the earlier mentioned yinsects. Vertebrates evolved from soft-bodied invertebrates.
Fish are six-limbed and are more similar to lobe-finned fish rather than ray-finned fish. Land vertebrates consist of a more primitive hexapod clade and a more derived tetrapod clade. Wormcows belong to the hexapod clade. Forest flyers may also be hexapods, with the middle pair of limbs evolving into leathery wings, making them look like bat-winged cats. This implies that different groups of hexapods and tetrapods convergently evolved things like fur and wet noses, perhaps more likely that tetrapods split off from hexapods after those traits were developed.
Exovoviviparans are part of the tetrapod clade, a retcon from the earlier statement that forest flyers are exovoviviaparans. I may also retcon the statement that exovoviviparans are widespread. They may in fact be rare outliers like the monotremes.
Exovoviviparity may be a highly evolved form of ovuliparity (where eggs are laid first and fertilized externally). Males may have first produced loose milt, then self-contained spermatophors, which gradually became externally indistinguishable from female eggs, including having yolk sacs.