Are a man's concealing from his wife before marriage significant physical defects (such as burns and severe flabbiness) and bad habits (such as smoking and shisha) considered legitimate defects, and is a woman entitled to seek divorce in this case?

The husband is not obligated to inform his wife of defects or bad habits that do not reach the level of repulsion. However, informing her is better to avoid discord. Smoking is forbidden, and repentance from it is obligatory. The wife is not permitted to seek divorce due to these defects unless she is harmed by them, or she dislikes her husband and fears falling short in her duties towards him.