Damdami Taksaal is from Baba Deep Singh & Guru Gobind Singh Jee. Not from Nirmala Sampardai. But the Vidiya/teachings are very similar.

You can't find Rehat Maryada in any Gurbani Granth. It is a collection of codes of conducts written by contemporary Sikhs of the times of Guru Gobind Singh - but it does include Gurbani to refer to how we should live & conduct ourselves.

The best thing to do is consult the Panj Pyaareh and the next Amrit ceremony. Go prepared to take Amrit and consult them before the ceremony starts telling them your situation. Whatever answer they give will be the best solution for you.

As the samosas were fried, the oil has gone into the pastry, and meat as well, which you still put in your mouth. Mistakes do happen, however you would need to go pesh at the next Amrit sanchaar and seek guidance from the Panj Pyaarey. They will be the best ones to advise you. 

The parkash of Sanchian, despite being Gurbani, is not considered as a single saroop of Sri Guru Granth Sahib Jee Maharaj, therefore the maryadha for keeping Sri Guru Granth Sahib Jee in a home does not apply. If it was a single saroop, then obviously it would not be right. Sainchian have been used for teaching and learning Gurbani for many years. Sanchian should also not be kept on top of each other at home, but should be kept side-by-side.

Despite the maryadha not applying here, we should have enough respect for Gurbani to treat any gutka, sainchi etc with the utmost respect. Sainchian should not be Parkash when unattended to or not being read. Respect should be out of love and reverence more than anything - not only maryadha. Every letter of Gurbani is Guru ang so the more respect, the better.

Bhai Gurdas Jee says,

'Vaheguru Gurmantar Hai, Jap Haoume Koyee' = The Gurmantar (Guru's Mantar, word to be meditated upon) is Vaheguru, by meditating upon it, your ego is erased.

No method of giving Naam is given preference - the only prerequisite is that Panj Pyare infuse it in the initiates (abhilakees) in an Amrit Sanchar in Maharaj's Hazoori. Bhai Sahib Randhir Singh wasn't given Naam by his Panj Pyare via this technique of Panj Pyare putting their hands upon his head, yet he rose spiritually very much. Once the Panj Pyare have given you Naam in your Amrit Sanchar all powers of Naam are infused therein. Some jathe do this parchar as per your query - but if their view is right then the method of given Naam reigns supreme over the actual Naam. In Gurbani you will only find praise of Naam & not any particular techniques.

The people who do this parchar as per your query actually believe that there is a difference in Amrit & Naam given by Panj Pyare but Gurbani says, 'Nanak Amrit Ek Hai, Dooja Amrit Nahe.' Many do fall foul of their parchar & go to their Amrit Sanchars to get 'their' Naam & end up having to re-take full Amrit again as their Panj Pyare don't believe in any other Amrit Sanchars as authentic. After a while people who do this realise they've made a mistake, that they questioned their Guru, their Amrit & their Naam. The technique they give is simple breathing 'Vahe' in & exhaling 'Guru' it is a good technique to use when you cant control your mind, but as you've already taken Amrit you can already meditate like this (in total there are 7 techniques with the breath to meditate on Vaheguru they only ever mention 1). Also some jathe conduct physical hugging after they give such Naam in their Amrit Sanchars, but the question then arises as to why this is done if the Panj Pyare have infused Naam, why the hugging? There is no justification for this hugging technique in Gurmat at all.