MB4 257b: Carrying if an Eruv Chatzeros and Shituf Mavuyos Were Not Done (388:1) Gentile Ownership of a House with Dual Access (389:1)

If an eruv chatzerot or shituf mavuyot were not made before shabbos then utensils in the mavui/chatzer can be moved but not between the chatzer/mavui and the houses.

If a gentile owns a house in a mavui and his house also opens via a window into a valley/karpaf or into another mavui does it ruin the eruv? What if the house is owned by a Jew? What if it's מוקף לדירה?