There are some things that make ablution invalid; such as any discharge from private parts and this applies to stool, urine, semen, blood and wind. Also Deep sleep and touching one’s private parts break ablution.

The unanimity of Muslim scholars agrees that a Muslim woman is not allowed to marry a non- Muslim including those who follow Bahai’ism as it is creed concocted with elements from Buddhism and other religions.

A Muslim woman can marry a communist only if he believes that there is no other deity than God and Muhammed is God’s messenger. In other cases it is forbidden. This article answers this question in details.

Muslim scholars have 2 different views on burying a Muslim in a coffin in societies where Muslims are minorities. The first discourages it and the second permits it in certain conditions as in case of soft land.  

It is forbidden to Muslims to eat any food certainly mixed with what is forbidden like pork. In case of doubt about it then the food is permissible to eat, because the normal ruling is that things are permissible.