To what extent are the prophetic injunctions directed to Ali (may Allah be pleased with him) authentic, and what is the authenticity of each individual injunction? Has anything been reported in the Sunnah that supports some of them, especially those related to blowing on food?

The aforementioned report has no established chain of narration (isnad) and is considered among the fabricated narrations by the Shia. The phrase "Do not sit among sleepers, nor sleep among those who are sitting" is among the virtues of etiquette. As for the prohibition of placing one's hand on the cheek or interlacing fingers, it is false and contradicts authentic narrations that permit it, except when awaiting prayer or during prayer. The phrase "Do not tear bread like meat" has no evidence for it. "Do not eat clay" is forbidden due to its harm. "Do not look into the mirror at night" has no evidence for it. "Do not wear a shirt inside out" is related to the ethics of chivalry (muru'a). As for the prohibition of blowing on hot food, narrations have been reported concerning it. "Do not sniff your food" is prohibited if it involves breathing into the vessel. As for "Do not yawn except with your hand over your mouth," the narration concerning it is authentic. "Do not look at what exits from you" is among good manners but has no evidence for it. "Do not enlarge your morsel" has no authentic narration, but making the morsel small is commendable. "Do not eat in the dark" is among good manners but has no evidence for it.