The Rohonc script appears to have on the order of one thousand glyphs. This is far more than one would expect in an alphabet or syllabary, but the most common glyphs are too common to represent morphemes.
It seems there is a relatively small number of core glyphs, some apparent ideograms, and several strategies to extend basic glyphs into more complex ones. These strategies include the addition of new lines and dots (C -> CE); the rotation or reversal of existing glyphs (C -> Q, XD -> XDA); and the use of ligatures (B + CU -> B1CU).
Similar strategies are used in some abugida systems like Ge'ez and Kharosthi, but the historical and geographic context of the Rohonc codex excludes any connection to these systems and their relatives.
I am not aware of any abugida system used in Europe around the 16th century. However, there was a system of scribal shorthand in use up until the 16th century called Tironian notes. Numerous extensions of this system were apparently developed with 1100, 4000, 5000 and 14000 notes.
Like the Rohonc script, Tironian notation has a relatively small number of core marks, extended to more complex marks using similar strategies to the Rohonc script. Indeed, an astonishing number of Tironian notae are similar to or even identical to Rohonc glyphs.
That is not to say that the two systems are the same. The most obvious difference is that the Rohonc script is written right-to-left. In addition, some I can't find Tironian equivalents for some of the most common Rohonc glyphs, and vice-versa.
However, among the writing systems that might have influenced the Rohonc script, Tironian notation has many features that make it a good candidate for further investigation.