Campaign AI

For the creation of a campaign similair to the officail ones, is it a simple task to create a basic AI for an enemy base that simply rebuilds what is lost and periodically sends attacks? Or is this a challenging task that I will have to find an AI scriptor for?

Building and attacking can be done quite easy in AI scripts. The stuff needed to do that can be learned quite easy.
Although the easiest way is probably to use the AI editor in TFT if the AI you need is very simple.