Salaam
If there is no non-mahram there, there is no need to cover her hair

Thank you for your question. It is a very wide topic and to capture all of its facets within a short answer is not easy.

Thank you for your question. I think that this is a misconception as all of the beauty and greatness of the Imams (as) is derived and inherited from the Prophet (saw) and so when the Shia praise the Imams (as) that is not separate from their appreciation of the Prophet (saw). From a theological perspective, the Shia need to discuss the qualities of the Imams to understand how they are rightful inheritors of the Prophet (saw) and for this reason, they spend time trying to understand those qualities.

May you always be successful.

Bismihi ta'ala

The literal meaning for the Arabic word nikah depends on how it is used in a sentence:

1. If it says nikah between a female and a male, it refers to a marriage contract.

2. If it says man did nikah with his wife, (nakaha), it means sexual intercourse. 

The technical meaning of nikah:

An Islamic contract between a female and a male, for the purpose of being together, intimacy, and forming a family. Of course, along with all the other conditions. 

Also see:

Bismihi ta'ala

If it is your house, then you must have authority over what enters it and what happens inside the house. Instead of getting to the stage of disowning, or expelling them from your house, try to get them to compromise. 

For example, ask them to cook their non-halal means outside. 

Also, continue to do as much dua for them as possible, that Allah ta'ala enlightens their heart and guides them. Remember that the dua of a parent is always answered.

Wasslam

Bismihi ta'ala

Regarding the Islamic etiquette of cutting nails, here are some points to consider:

1. It is recommended to cut nails on Fridays, and it is also the best day to do so.

2. Other days that have been mentioned as recommended days for cutting nails are Tuesday and Thursday.

3. If you do cut your nails on a Wednesday, start with your right pinky nail, and end with your left pinky nail.

4. It is very detested to chew on nails, or cut nails with teeth.

5. When you cut your nails, say:

Bismihi ta'ala

Marriage is based on sacred commitment, love, respect, honour and tolerance. Each of these features is a fundamental pillar of marriage. Anything that disturbs the internal cohesion of a spousal relationship must be avoided. 

This married man is doing wrong by neglecting his wife, and this could lead to oppression. Should he have issues with his wife, they need to be addressed through communication, or through counceling.