What is the ruling on one who entered the Hijr during Tawaf in Umrah, being ignorant of the ruling, and then returned to his country and performed other rituals?

A circumambulation (Tawaf) performed by the questioner from inside the Hijr is invalid because the Hijr is part of the Kaaba. Since she performed the rituals of a second Umrah, it suffices for the first one, and her second ihram (state of ritual consecration) is considered void. She must offer expiation (fidyah) for the ihram transgressions related to damage (like shaving, shortening hair, or clipping nails). This expiation can be fulfilled by fasting for three days, feeding six poor people, or sacrificing a sheep in the Haram. There is no penalty for transgressions related to luxury (like wearing perfume or certain clothes) due to her ignorance of the ruling.

As for performing Umrah on behalf of another, it is a condition that the performer has already completed his own obligatory Umrah. Furthermore, the one on whose behalf the Umrah is performed must either be deceased or alive but physically incapacitated, with their permission. Otherwise, the Umrah will be counted for the one performing it.