Did a backup of 2um3pm non root. Blew instances away and created fresh install on new instances. Now restore to this instance complains:
2018-12-15 05:08:25] ERROR: PM1: data directory found – /home/mysql/mariadb/columnstore/data1/000.dir
[2018-12-15 05:08:26] ERROR: PM1: dbrm directory file found – BRM_savesA_em
[2018-12-15 05:08:26] ERROR: PM1: dbrm directory file found – BRM_savesA_vbbm
[2018-12-15 05:08:26] ERROR: PM1: dbrm directory file found – BRM_savesA_vss
[2018-12-15 05:08:26] ERROR: PM1: dbrm directory file found – BRM_savesB_em
[2018-12-15 05:08:26] ERROR: PM1: dbrm directory file found – BRM_savesB_vbbm
[2018-12-15 05:08:26] ERROR: PM1: dbrm directory file found – BRM_savesB_vss
[2018-12-15 05:08:26] ERROR: PM1: dbrm directory file found – BRM_saves_current
[2018-12-15 05:08:26] ERROR: PM1: dbrm directory file found – BRM_saves_em
[2018-12-15 05:08:26] ERROR: PM1: dbrm directory file found – BRM_saves_journal
[2018-12-15 05:08:26] ERROR: PM1: dbrm directory file found – BRM_saves_vbbm
[2018-12-15 05:08:26] ERROR: PM1: dbrm directory file found – BRM_saves_vss
[2018-12-15 05:08:26] ERROR: PM1: dbrm directory file found – oidbitmap
[2018-12-15 05:08:26] ERROR: PM1: dbrm directory file found – SMTxnID
[2018-12-15 05:08:27] ERROR: Table data was found. Cleanup the installation and rerun.
[2018-12-15 05:08:27] Restore Status: Failed

Clearing:
rm -rf mariadb/columnstore/data*/data1/systemFiles/dbrm/*

solved this but seems like a restore should just work on a fresh install? Also even if it's not its kind of clunky to make users go through a gazillion steps on each node to do a restore (this has to be balanced against accidental restore of course).