Rank indicative adjective

Solution 1:

Was there any old usage of position indicating adjectives in English... like Potter stood in the "twoeth" place in the class or Rachel was in "foureth" place,

No, first second and third were irregular but the rest are regular.

forma - first
ōðer - second (compare Modern English "other")
þridda - third

You seem to be confusing Old English (incomprehensible to Modern English speakers) and Middle English (difficult to understand for most Modern English speakers) with some invented version of English found in cheap novels.

"foureth" (fēorða (OE) - fourth) is completely wrong - "eth" was either "eth or "th" depending upon the previous sound. You should use the current version that does not have an "e" - fourth

Five was originally "fif" so "fifth" is also regular.

https://en.wikibooks.org/wiki/Old_English/Numbers