Technique learning is more or less randomized, yeah. It kinda sucks. Characters will always learn the same techniques in the same order, but the levels they get them at are somewhat randomized. Here's the notes I have on it in my walkthrough, which is still being written:
The data on which level the characters will learn their techniques should be
taken with a grain of salt, as it appears it's random as to whether or not
someone will acquire one or more techs at level up.
You may run into a case where someone will learn a tech a few levels earlier
or several levels later than the data I found, so don't fret--this is normal
behavior!
However, I have confirmed for a certainty that they will learn their tech
set in the order listed. Just think of my tech/level up data as being
"around the time a character can possibly gain this technique."
Furthermore, the actual techs are somewhat wrong on the PS Cave PSg:2 section and on Wolfgang Landgraf's site. Here's the actual data I have so far. Again, take the levels as a grain of salt. One time I had Eusis learn Water, Zonde, Nafeuer, and Gizan all at LV 20, and the other time he learned Water and Zonde at LV 20, Nafeuer at LV 22, and Gizan at LV 27
EUSIS:
Feuer - Known initially
Rückkehr - LV 9
Gifeuer - LV 10
Glanz - LV 10
Hinaus - LV 13
Zan - LV 13
Rester - LV 15
Gravito - LV 18
Giglanz - LV 19
Water - LV 20
Zonde - LV 20
Nafeuer - LV 22
Gizan - LV 27
Girester - LV 27
Gizonde - LV 28
Giwater - LV 28
Naglanz - LV 34
Nazan - LV
Gigravito - LV
Reverser - LV
Megiddo - LV
NEI:
Rester - Known initially
Anti - LV 27
Sacra - LV 35
Nasacra - LV 41
Shifter - LV 53
D-Wand - LV 57
Narester - LV 61
Saschutz - LV 65
Saschneller - LV 70
Nasarester - LV 77
ANNE:
Rester - Known initially
Schutz - LV 5
D-Wand - LV 9
Anti - LV 9
Feuer - LV 10
Girester - LV 12
Sarester - LV 16
Sacra - LV 18
Nasacra - LV 21
Narester - LV 25
Saschutz - LV 25
Saschneller - LV
Reverser - LV
Gisarester - LV
Nasarester - LV
Gravito - LV 61
Gigravito - LV 77
HUEY:
Limiter - LV 4
Genera - LV 5
Drunk - LV 5
Water - LV 7
Sagenera - LV 8
Shinparo - LV 8
Seizures - LV 10
Rester - LV 13
Feuer - LV 14
Giwater - LV 16
Gifeuer - LV 19
Volt - LV 23
Zan - LV
Gisawater - LV
Savolt - LV
Gravito - LV
Girester - LV
Gigravito - LV
Gizan - LV 59
AMIA:
Feuer - Known initially
Schneller - LV 12
Shifter - LV 15
Vampir - LV 26
Zan - LV
KEINZ:
Feuer - Known initially
Falser - Known initially
Ager - LV 8
Zonde - LV 11
Gadge - LV 12
Konter - LV 15
Limit - LV 15
Gigadge - LV 16
Zan - LV 16
Gizonde - LV 19
Sagadge - LV 20
Gravito - LV 23
Nagadge - LV 28
Gisazonde - LV
Gisagadge - LV
Prozedun - LV
Nasagadge - LV
Gizan - LV
SILKA:
Feuer - Known initially
Rückkehr - LV 10
Hinaus - LV 13
Rester - LV 17
Gifeuer - LV 22
Zan - LV 30
Gravito - LV
Gizan - LV
Girester - LV
Nazan - LV
Gigravito - LV 57
Nagravito - LV 68
Everyone has the same tech loadouts as the Genesis original, basically. Aside from Nei.
Also known as vivify93.