The issue here is shown by two specific bits of information from the error message:

 FUNCTION: DB2 UDB, high avail services, sqlhaGetParentResourceGroup2, probe:300

and

 Line # : 15656---2610-407 No resources found.

So in this case db2haicu was looking for the parent resource group for the IBM.ServiceIP resource db2ip_10_10_10_175-rs and was not finding it. It found the IBM.ServiceIP but could not find the resource group that the SIP belonged to which means that the SIP was unmanaged.

When db2haicu goes to delete an instances configured clustered resources it lists all IBM.ServiceIP's and attempts to ensure that they do or do not belong to the resource group of the instance being removed. In this case it found a resource that could not be tied to a group and this stopped db2haicu from carrying out the rest of the deletion.

To resolve this you should manually remove the db2ip resource from the cluster because since the resource is not contained in a resource group it is not being managed/automated by TSAMP anyway so has no use in the cluster.

To manually remove the above shown IBM.ServiceIP resource use the following:

 export CT_MANAGEMENT_SCOPE=2
 rmrsrc -s 'Name ="db2ip_10_10_10_175-rs"' IBM.ServiceIP Force=1

The above command will remove the IBM.ServiceIP resource even if it is online but will not take the alias offline (tested on AIX 7.1 only).

If you need to manually assign or remove an IP Address alias please see the following knowledge article:

How to manually assign or remove a virtual IP address when TSAMP is in Manual mode or the domain is offline