Moving into a new home

Q: I am moving into my new house which has just been renovated. I called a Shaikh for dua and food and I have also fed my immediate family members and neighbours on that day. Is this bid'at? I am a bit worried. I have been correcting my intention doing it to please Allah and not to please makhlooq. What should I do immediately after entering the home? Me and my wife were thinking of performing two rakaat of Salaah and making dua, then reciting Qur'an and making ta'leem of fazail. Can you please advise.

Making jamaat

Q: Is it permissible for a mother and son to perform Salaah together in Jamaat? If so, where should the mother stand and is it necessary for the mother to give the iqaamah?

Adab and respect

Q: I want to ask regarding the adab of not calling a person's elders using the word 'you' , but rather repeating their title e.g. moulana

1) What are the origins of this and which kitaabs is this mentioned in?

2) In Arabic when addressing Nabi (Sallallahu Alaihi Wasallam) in madinah munawwarah, the word ka / you is used. Also when making dua to Allah Ta'ala both in English and Arabic, does this not then become much more disrespectful than using the same word you for some elder?