Few thoughts Bairagi ji
This is preached a lot today but it wasn't the case back then. Points i and ii are the reality IMO. Also Rajput and kshatriya, and even Shaiv Panthis started filling up the Khalsa ranksin huge numbers. Being, warriors these communities thought it was their duty to fight in a Dharam Yudh announced by Guru Gobind Singh ji. Most of the warriors during his time were warrior caste. To them Guru ji himself emphasizes his warrior caste, and fighter nature saying I am the son of a Kshatriya, not a Brahmin, (read: I am someone who will fight in battle than someone who studies battle) when announcing himself as the head of this yudh in northern India.
Apparently only 3 kakkars were mandatory then. Kes, Kara and Kurd or Kes Kachha and Kurd. Though I can't remember which 3 exactly, since it has been a long time since I read material on the early rehitnamas.
Kara symbolized commitment to the dharam yudh.
Kachhera is exactly like a dhoti. One is wrapped the other is tied. But there is one advantage to Kachhera and that is that it can have threaded bottoms that can be tied to secure it around the knees to prevent insects from crawling up. This cannot be done with dhoti nor loin cloth.
Singh is the warrior (specifically the Rajput community) last name. He was making his sikhs into warriors so he gave them a name to match. Also because most of the warriors in his army would have been Rajput. It's not like one day he said everyone is a warrior, and everyone knew how to fight. No, first those who already fought, came in then others adopted the name. Guru Sahib adopted it himself as well. The name was associated with rulers and warriors of India (Rajputs) who had defended it over centuries. It was only natural to give this powerful name to soldiers in his own army. Even so, he commanded a larger mercenary Muslim, Pathan force (Pathan is another one of these powerful warrior figures alongside Rajputs).
I think you'll be interested in this lecture on Sikh arms and armour: In Praise of Steel Nihang History -Davinder Singh Toor - YouTube
