Is designing logos that do not contain a soul, such as drawings of fruit, considered doubtful or unlawful? And am I sinful if the buyer uses the logo for an unlawful purpose? And is it permissible to sell on non-Islamic websites that charge a commission?

It is permissible to design logos containing drawings of inanimate objects, such as fruits, and it is permissible to sell and buy them from non-Muslims. As for selling something that is originally permissible and can be used for both lawful and unlawful purposes, it is permissible, except to one who is known to use it for unlawful purposes; in such a case, it is prohibited to sell it to them.