How would you describe the architecture of a Muslim family's house - I mean, should there be a separate living room for males and females, especially when in-laws come to visit, should there be a prayer room for the ladies etc.

All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.

Undoubtedly, it is better, for whoever has the means, to plan his house in a way that there is a separate sitting room for men and another one for women, especially when one has visitors. This is absolutely better when families gather in order to avoid temptation.

However, this planning is not an obligation, but it is an obligation to avoid the means of temptation and corruption. Women should not speak in a soft voice with men; Allah Says (what means): {…do not be soft in speech [to men], lest he in whose heart is disease should covet.} [Quran 33:32]

Also, they should not speak to men without a need, and when the need arises, then talking should be according to what is necessary, and they should observe the Hijab.

Meanwhile men should lower their gaze and not talk to women except in case of necessity.

Allah knows best.