Recipe calls for Tapioca pudding - none to be found!

I've seen recipes that does not use tapioca pudding (just jello and vanilla pudding)

The final consistency will not be the same, but it should work.

https://parade.com/841414/kristamarshall/popsicle-in-a-bowl/

https://www.madetobeamomma.com/creamsicle-fluff/

Tapioca pudding is obviously based on tapioca starch. I don't know what kind of commercial product is usual in your part of the world though.

The simplest case would be if the product you are meant to replace is pure, powdered tapioca starch. In that case, any starch will do. The more glutinous the starch, the closer the result will be to the original, so potato flour or arrowroot starch will be better than cornstarch, for example.

If the original product is a mixture of starch, sugar and flavorings, you will have to find out the ingredients (maybe look up brands which are popular in your cuisine online, they frequently list ingredients) and make an appropriate replacement, by adding sugar and maybe some flavor.

If you are supposed to replace pressed tapioca spheres, then your best option will be to use rice. Choose a style intended for milk rice. I don't think this case is very likely, because I don't imagine creamiscles as containing tapioca spheres, but I am mentioning it for completeness.

Alternatively, you might try to find tapioca pudding in Asian food stores or online, it is not that difficult to find if you live in a country that imports a variety of international foods.

The definition of Tapioca pudding is:

Sweet pudding thickened with tapioca.

I see you have pudding, you should be able to take some of the pudding and heat it up with some tapioca starch to thicken it, and bam! You have yourself a tapioca pudding substitute.

If you don't have any tapioca in your house, you can try thickening the pudding with corn starch instead.