AIX

Definitely IBM VM Recovery Manager DR.  For HA solutions think about IBM Power HA or MiMiX HA for AIX from Precisely.  

Thanks Igor.  Are the documents readily available on setup and other steps for these three technologies.  Please advise.  Thanks.

All HA/DR solutions require experienced system and application administrators plus vendor/partner support.
IBM documentation is available online (https://www.ibm.com/docs/en/powerha-aix/7.2.x , https://www.ibm.com/docs/en/vmrmdr/1.9.0)
and huge amount of valuable information contain also IBM Redbooks (https://www.redbooks.ibm.com/).
Ask Precisely.com for their documentation resources.
Such products are strictly licensed but you can ask vendor's representative for demo license.

[not really an answer per se]  I agree with @Igor Novotny on the main points.  I'm a little concerned about how you mean "orchestration" in the context of "lots of AIX LPARs".  How are they managed and orchestrated at the source site(s)?  Do they need to be brought on-line in a very specific order (LPAR by LPAR, cluster by cluster, etc.) at the DR site?  And, should we assume that there's relatively identical (or close enough) storage, compute, and networking available 24x7x365 in some kind of warm site?  Different/incompatible storage at the sites could knock some suggestions out immediately...

hi

 IBM VM Recovery manager for Power is the solution for your inquiry , please check below my article written two weeks ago

please check below link for IBM VM recovery manager for Power written two weeks ago

https://community.ibm.com/community/user/blogs/anas-alsaleh/2025/11/11/bm-vm-recovery-manager-for-power

thank you 

IBM Virtual Machine Recovery Manager for IBM Power Cookbook
https://www.redbooks.ibm.com/redbooks/pdfs/sg248539.pdf