I haven’t no good answer for ‘next night’, but I commend to you ‘yestreen’ — a word meaning “yesterday’s evening”, which was still in (possibly) use in the 19th century. Is it ‘yestereven’? See also ‘forenight’. The next time that the word “yestreen” occurred was 3600, not necessarily old English, but definitely unlike modern English.

Also, you may be happy to know the existence of ‘Saturnight’, ‘Sunnight’, ‘Tuesnight’, ‘Wednesnight’, ‘Thurseven’ and ‘Frinight’. In all cases, these referred to the night prior to the corresponding day. All were labelled Old English (also earlier than 1400).

This is the OED’s earliest noted use of ‘Thurseven’: Against Elf-Sickness (Royal 12 D.xxl) in

G. Storms Anglo-Saxon Magic (1948) 222 Gang on unres fen, onne sunne on setle sie, r u wite elenan standan.

I am supposed to be able to help you with a translation. Can you help me with translations?

What do you mean by “The end of the night, just before daybreak”? If that’s you then you’ve met ‘ughten’ I believe that Beowulf is in the Germanic/Saxon/Old-English mishmash at the time.

Straying into invention, I suggest ‘to-fall’– a word meaning ‘beginning of night’, whose examples in the Oxford English Dictionary (which I’ve used for all the words listed) all look to the future. Has the French words been used since 1475?