Is a man's inserting his finger into his anus consideredzina or sodomy, and can he marry Muslim women in this state, and is the حد (prescribed punishment) applied to whoever commits this act in Islam, and does this fall under the principle of "the fornicator shall not marry except a fornicatress"?

It is not permissible to intentionally insert a finger into the anus without a legitimate Shariah need, and it is forbidden for both men and women. However, it is not considered zina (fornication/adultery) or liwat (sodomy), and the hadd (prescribed punishment) for zina or liwat is not applied to the perpetrator. This forbidden act does not prevent the perpetrator from marrying someone whom he is permitted to marry, nor does the verse apply to him: "The fornicator does not marry except a [female] fornicator or polytheist, and the fornicator is not married except by a [male] fornicator or polytheist. And lawfully forbidden to the believers is that."