Migration doubt

Scenario is: 4 serie i2600 forming sync-group GTM. Being two diferent cluster HA active/standby LTM. First ill change one pair and another day the another.

My idea for migrating an LTM/GTM pair from the iSeries platform to the rSeries platform is as follows:

We used same cables from i series and same names and IPs to do it easier to customer

First, I disconnect all the cables from the standby iSeries unit. The active iSeries unit will remain active in standalone mode.

Next, I connect the interfaces used for the synchronization and failover network from both iSeries appliances to the new rSeries appliances. The HA pair has already been configured on the new rSeries units, so one will be active and the other will be in standby.

Once the standby rSeries node is in place, I connect all the service cables to it. After all the service cables have been connected and I have verified that everything looks correct (ARP entries, pools, etc.), I proceed to run the bigip_add and gtm_add commands against the active iSeries node.

It is important to note that the iSeries and rSeries appliances will never form an HA cluster with each other.

After running both commands, I verify that everything is operating correctly before forcing the active iSeries node offline and allowing the rSeries node to become active.

If I face any issues while running the bigip_add or gtm_add commands, since the new rSeries nodes use the same hostnames and IP addresses as the previous iSeries appliances, I may need to remove the trusted certificates associated with the old appliances from the other BIG-IP devices before attempting the commands again.

Anything to keep in mind? or any potencial issie doing like that?? Would it be necessary or recommended to temporarily take the GTM cluster being migrated out of service, or is there no significant risk in keeping it operational?

Its my first GTM migration in a bit lost.