Open questions
One question, and what would settle it.
Does the Ranjana tradition count the six aspirated sonorants of Nepal Bhasa, ngha, nyha, nha, mha, rha and lha, as letters of its own varnamala, or as conjuncts of a base letter with ha?
Why it is open. Ranjana is unencoded, so there is no character standard to settle the inventory. The one openly licensed Ranjana typeface, Nithya Ranjana, ships two builds: the Devanagari-mapped build has no way to reach these six, because Devanagari has no letters for them, while the Newa-mapped build carries a separate outline for each, since the Newa block encodes them as letters of Prachalit. The font therefore draws six shapes whose status in Ranjana's own tradition this run could not establish, so the 47 letters seeded here are the vowels and consonants both builds agree on.
What would resolve it. A reading of Newar alphabet charts and primers that teach Ranjana in the Kathmandu Valley, or of the Ranjana Unicode encoding proposals submitted to the Unicode Technical Committee, either of which would state whether the six are counted as letters. If they are, they belong in the block at ids 5247 to 5252.
Field. Newar palaeography; South Asian script encoding