Taking a second wife

Q: If a man's wife becomes ill and sickly and therefore she will be  unable to satisfy his sexual desires, would it be ethical for a man to get another wife or will it be unethical. The man will still dedicate his time to take care of her needs. He will not desert her. In terms of shariah, does it become compulsory for the man to get another wife if he still has a lot sexual desire in him? If he does not get another wife out of kindness and service to his first will, will this be considered as being foolish while he still has sexual desire and cannot satisfy himself with her?

Wudhu breaking through touching one's wife according to the Shafi'ee mazhab

Q: A shafi follower makes wudhu according to Shafi'ee fiqh and then mistakenly touches his wife without any piece of cloth in between, and this person knows that according to the Hanafi maslak his wudhu did not break and goes and prays fardh salah according to Shafi'ee fiqh without renewing the ablution (to make his life easy). Will his Salaah be valid as he is basically a Shafi'ee. Note that he does not do this all times it occurs very rarely?

Seeing the girl before marriage

Q: Is it permissible for a boy who wishes to get married to see the girl? Nowadays when the boy goes to see a girl, then they both sit and speak?
Is this permissible if done in the presence of the girls parents? I am not speaking about after the proposal is accepted by the girls party for boy and
girl to meet and speak. I know this is not permissible.

Building above the Musjid

Q: Is it permissible to build a musjid with three flats on the top. One for the Imaam, one for the Mu'azzin and one to give on rent as income for the Musjid. If other accommodation is later on found for the Imaam and Mu'azzin, and the place becomes vacant, can the three flats be given on rent
for the income of the Musjid?