Laurent,
According website honorstates Van Vliet flew with the 27th FBG, flying A-36 Apaches (see
https://www.honorstates.org/index.php?id=334573
However,an Honor Roll doesn't mention him:
http://raf-112-squadron.org/27thfghonor_roll43-44.html
As for Essigmann (double "N" at end), this story (account at the bottom) appears to point to some ground crew also killed in the 42-30121 accident:
https://www.reddog1944.com/SLATEN_97th_BG_414th_BS.htm
Leendert