Is a marriage Haram if only eight people (four of the husband's friends and four of the wife's friends) know about it, and not the families of the husband and wife?

Marriage without a wali (guardian) is invalid, and the couple must be separated. If the wali approves it afterward, it should be with a new contract after the woman has completed her istibra' (period of abstinence to ensure non-pregnancy), if intercourse has occurred, or by the wali's ratification according to some scholars. As for marriage without public declaration (ishhar), if it was not done by mutual agreement (to conceal it), it is valid, but it must be announced. If it was done by mutual agreement (to conceal it), there is a difference of opinion among scholars regarding its validity. Some invalidate the marriage due to its resemblance to zina (fornication), while others validate it because its conditions of validity are met.