I find this argument to be a little troublesome. A very "western" approach to Sikh history is being taken. By that I mean you have exclusively relied on surviving documents to "prove" that the Budda Dal was not the Panjva Takhat. At the same time, you have shunned every bit of Seena Baseena Tradition within the Dal Panth. This is a very western approach to doing research - Western academics are notorious for relying exclusively on existing documents and then arriving at conclusions while rejecting the oral traditions of the group they are researching. This is troublesome because "writing things down" is largely a Western concept and for centuries non-white people around the world focused on orally transmitting history. When you ignore the seena baseena traditions of non-western groups and individuals and rely exclusively on "things that were written down" you inevitably arrive at half truths and fallacies
A paragraph from a essay i recently read comes to mind:
"Before an examination of the issue of Sikh identity can take place, it is important to first acknowledge the limitations of the historical, and specifically Western approach to studying the Sikh tradition. Noel Q. King holds the view that using methods of scholarship developed for Christianity and Judaism on other religions, is dangerous. This observation, of course, is very much linked to the debate of Orientalism: a western ethnocentrism that sees the norm as being the West and all other traditions are judged by those standards and considered mutations of the same. In the Sikh tradition, a major method of transmitting history and tradition is oral. This is not acceptable for scholars who would use the Western approach: a codified, written account is needed. A good example of this conflict can be seen in the examinations of the Rehitnama literature. Although rehit is considered to be a comprehensive guide to the Khalsa code of conduct, it was often written as a supplementary guide to the Rehit outlined by the initiating Punj Pyaaray in the Khanday kee Paahul ceremony. Desa Singh writes in the seventh stanza of his rehitnama, “that rehit which the five utter, keep that steadfast in your mind” and later in the ninth stanza writes “that is the first rehit, the one which the five Singhs said in the Paahul ceremony. The other different rehits which are spoken of, that is which I will go on to explain ”. Clearly the written rehit is secondary to the one which was orally elucidated by the Punj Pyaaray. Even to this day, many Sikh groups i.e. Akhand Kirtanee Jatha, keep the rehit and the gurmantra secret and a guard is posted at the doors of Paahul ceremonies to maintain secrecy. The rehit is passed down orally through generations or “seenaa-baseenaa” and the newly initiated are instructed to carefully listen and remember the rehit so that they too may pass it down. The modern day “Sikh Rehit Maryada” which was created in the first half of the twentieth century is in fact a western document which is formally codified in prose with sections and subsections and is not in any way a “traditional” Sikh document...Thus, attempting to analyse and understand the Sikh tradition with a west-centric view is difficult and prone to error...."
So, in my opinion, our ancestors could very well have viewed the Budda Dal as the Panja Takhat and there could very well have been 4 other Takhats (Akal Takhat, Patna Sahib, Kesgarh Sahib, Hazur Sahib). Regarding the argument presented about how "according to written codified evidence" these places didnt refer to themselves as takhats...well imo that is irrelevent as even the Akal Takhat was referred to as the Akal Bunga in many cases, the absence of the word "Takhat" in this situation doesnt mean that it wasnt a Takhat.
Pardon any mistakes I have made. Just trying to provide a prespective opposed to the one presented above. I am not arriving at conclusons. Personally, i myself am undecided on this issue surrounding the Budda Dal.