There is a group of Singhs in the uk who met with Baba Ji in 1999 when they were doing Tap at Guru Ka Lahore. There are also pictures from this time as well. To say Baba Ji went into hiding to live another life is quite absurd. Ask those who did Seva of Baba Ji when they stayed in California.
Budha Dal had responsibility to give pahul to the whole panth including Maharaja Ranjit Singh's times. So their maryada would have normally been used and should be authentic. Hajoor Sahib should also more or less keep the same or similar maryada to Budha Dal.