Is it permissible for a suitor to establish tourism websites that will be owned by individuals who may post women's pictures or deal with Israeli entities, knowing that the suitor may later be asked to make modifications that involve Sharia violations?

The basic principle in website design is permissibility. However, if the designer knows that what he will do will be used for something forbidden, such as nude images or tourism that is not compliant with Islamic law, then it is not permissible for him to do it, because it involves assisting in sin.