The only arachnid in your post is the spider. All the other creatures are insects. And insects and spiders are two different types of creatures within the phylum Arthropoda.
Insects belong to the subphylum Hexapoda, class Insecta. And the name "Hexapoda" means "six legs", which is the main identifying trait of insects. If an arthropod has more than six legs it is not an insect.
Spiders belong to the class Arachnida from the subphylum Chelicerata. And the main identifying trait of arachnids is having eight legs. Spiders are not insects.
As for other differences that differentiate the two, insects have three body segments - a head, thorax, and an abdomen. Spiders only have two body segments - a cephalothorax (combined head and thorax), and an abdomen.
So there, I hope this explains it well. A spider is not an insect, because it is an arachnid. And arachnids are not insects. 🤓 🙂 💡
Woow! Thank you so much for this @kryptik.tigrrr3d! I never thought its classes, the phylum and others. You explains well to this sir! Well, I admit that this is based in my own experience and what I have seen in actual. I am so sorry for the lack I have made.
Thank you for this and have a blessed day!