Straightening the Saffs in Salaah

Q: It comes in a Hadith that straighten the rows, the word "taraas" has been mentioned which means join like a brick wall with no gaps. So why do we not join the feet and only the shoulders. Also, what does it mean by close the gaps shaitaan will come in-between? Also, if the companions joint their feet an shoulders should we not follow them in the beggining of Salaah? And is it nessasary to join the shoulders? Please give me daleel as these are people's questions. Where I give dars.

The name "Shasmeen"

Q: What does the name Shasmeen mean? Is it a good name to keep for a girl? Also I'm looking for a name for a boy that would not be mispronounced with regards to the correct tajweed pronunciation.

Purdah between husband's and wife's children from previous marriages

Q: Is there purdah between the husband's baligh son and the wife's baligh daughter from a previous marriage? Would they become milk brothers and sisters if the new wife has a baby from her husband and breast feeds the baby? Will the breast feeding of this mutual brother and sister render his and her children milk siblings. Please explain the ruling according to hanafi and shafi.