It is sufficient.
Demolishing a mosque is not permissible but if it collapses itself it is permissible to use its materials to rebuild the mosque of that village or other places.
About mosques that are situated in the middle of streets, there is no way that they can be demolished, both because they are mosques and because the property on which they have been built has been devoted by someone to the mosque. Thus anyone who demolishes such a mosque should pay the price for that by building another mosque or repairing other mosques. In fact, this is an example of wasting the property itself and until there is no necessity, destroying a mosque is strictly impermissible. As regards desolate mosques in deserts and desolate villages, they should be kept in a way that they are not desecrated.
The obligatory precaution demands that infidels be prevented from entering mosques except when they intend to research about Islam and like that.
Performing these acts in the mosque is not prohibited and there is no need for the permission of the religious authority. However, attending to worldly acts in the mosque is considered to be makrūh and if these acts disturb the worshippers in the mosque they are prohibited.
If rows of women are behind men there is no need for a curtain but if they are beside each other the obligatory precaution demands that a curtain separates them.
There are some limitations for women and sometimes for men for entering mosques; however, there are much fewer limitations for entering hussainiyyahs. Of course one will be granted a much greater reward for performing prayer in the mosque compared to a husainiyyah and this is why both kinds of building are constructed.
It is not permitted, but if the person who devoted the land for the mosque has allowed it, it will be permissible. However, there is no issue with constructing things like libraries in the basement of the mosques.
This is not permissible, but it is permissible to sell them and use the money for other needs of the mosque.
It is not permissible based on the obligatory precaution; however you can open a door from one mosque to the other.
There is no issue with it if it doesn’t disturb the worshippers and it doesn’t reduce the place for performing prayers and it is a necessity for the mosque.
There is no problem with it if the mosque is not decorated with gold and the picture of living creatures and on the condition that it does not lead to extravagance and the wasting of resources.