I would speak to the vet personally.
I have the box for the spot on........profender and the one I had for Lupin was for small cats 0.5kg - 2.5kg so sounds like this can definately be used on a kitten.
The small millibax pill has only be fed to Misa so no idea about that.
Pretty certain that panacur the powder that mixes with food will be able to be used for a kitten but will need checking but as I recall Lupin was given a number of doses of this on the trot.........maybe part sachees but cant remember.
When he came to me he had an appalling upset tummy and all of this was to make sure he had no worms,,,,,,,he didnt and it didnt solve the problem!
I only have mine wormed once a year Misa gets millibax, Lupin will get prefender cos he is a pirahana and once i am able to get Sasa to the vets, she will have an injection, cant remember what its called but it means that she can then also have Stronghold. Otherwise she would have to wait for 1-2 weeks for the stronghold cos if she had profender cos they cant be given together.