If there is no LUNs bound, you may delete them without any issues. Hot spare will have a private LUN bound on it, you can delete that also without any issues if required.

You may also create single RG on it. Below link provides the best practices while creating RG and LUNs.

White Paper: EMC CLARiiON Storage System Fundamentals for Performance and Availability — Applied Best Practices

i deleted the rg 171. then tried to expand rg 170 by adding the 2 disks from the previous rg 171.

but got this error

SPA: Bad FRU configuration in expansion request

how is it possible that i have 2 rgs with the same disks on 2 rgs?

bus2 enclosure 3 disk 12 and 13

Have you expanded RG 180 accidentally instead of RG 170 after destroying 171 ?

rg 170 and 180 ae 2 separate expansions. basically, when i go to rg 180 and then go to disks and expand, i was able to see the 2 available disks 12 and 13. so i used them for expansion. but then noticed that rg 181 was using them. so the question is why would it show as available disks if another rg is already using them?

What are the RAID types used here ?

Can you post a snap of the properties of RG 171 ad RG 180 (which are having the common drives).