As Michael mentioned Prores 444 is your best bet for maintaining a high quality/resolution file that Avid can use. DPX renders are just not going to work in Avid unless you use the third party app Gluetools. Any other image sequence is just not worth the hassle as for the lack of Timecode metadata and eye matching.
Hopefully by NAB Avid will get DPX going as they seem to be “working on it”
Lustre can create Avid MXF files as well but limited to YUV codecs only and no RGB options.
You should check with your post house as Lustre requires a headless Mac to process the Prores files through their conversion app “Wiretap”.
if they are running Flame Premium which has Lustre as part of their package, the Prores encoding is possible on their RedHat Linux station.
If it is Lustre standalone, no dice.
You could translate their provided dpx graded clip sequences yourself but that requires Resolve or some other conversion process.