Making the entire upper floor a masjid without having a sehen

Q: Insha Allah, our masjid will be doing some extensions. We will be extending by putting an upper floor. I wanted to find out, if the ground floor has a masjid and a sehen, is it permissible for us to make the entire upper floor a masjid without having a sehen?

For example, if the bottom floor is 500 square meters (300 sqm is the masjid and 200 sqm sehen). Can we make the entire upper floor (500 sqm) masjid?

Masjids built for collective worship

Q: Those that advocate continuing closure of the Masajid, even for individual worship pose 3 questions:

1. Is it permissible to use the lighting in the Masjid for times other than when collective worship takes place?

2. Did Nabi Sallallahu Alayhi Wasallam encourage individual at home or the Masjid?

3. Are Masjids built for collective or individual worship?

These 3 points or questions rather are being used to promote the continuing closure of the Masajid. Are these valid points? I suspect they are not, and have some proofs, but I can’t be certain if they are correct.

Repairing damaged Quraans from the musjid and keeping few copies at home

Q: My husband bought some damaged Qurans from the local masjid to our home around 18 months ago. He repaired the broken spines and returned many. However he has kept a few in our house and also in my in laws house because they are large print. At the time I raised my concern they are community property. Im concerned they are waqf, perhaps donated by someone in the community for local charity, and now we have them in our house and my in laws house. Neither house (mine or my in laws) refers to them.

Should we return the Qurans or keep them? If we must return them what should we do as repentance?