Prayer

The authentic hadeeth stated some 30 angels and not 30,000

It should be said loudly

This is highly recommended

no problem.

There is no limit the only thing is that it should be even number and you conclude it with witr so that total would be odd number

If he is traveling between two cities, you don’t have to pray Juma’ah. But if you are staying in a town and the Jum’ah is called, you must attend it.

This is an issue of dispute. The safest opinion is to pray it 2 by 2.

Yes, this is the Sunnah of the Prophet salla Allahu alaihi wa sallam.

No, you must pray the whole thing with the same Imam.

This is something between you and Allah. If you know that this is essential for your health, this is permissible. But if you go out and live normal life except that you don’t go to the masjid, this is not permissible.