Migration from physical Device 5000 series to F5 VE

To be honest it is probably wisest to contact your local F5 sales or F5 partner as there are lots of factors to consider.

But if you dont want / cant some useful things to know is what the current throughput and load is. Also any expectations about grow in the future.

Are you planning two VEs? Where do you plan to deploy the VEs? Same physical environment but on a hypervisor? Which hypervisor? Version number isn't something you can select, just take the latest, it allows older versions to be installed also, it is for the last upgrade you can do. I would install the version you are currently using for an easier configuration migration.

For doing this without affecting production I would advise you to not have that as a goal. You might get close but makes things way easier on yourself if you just start perparing people for a couple of hours of expected downtime and are able to pull it off quicker and make everyone happy.

Something similar was asked here: https://community.f5.com/t5/technical-forum/virtual-f5-vs-hardware-which-one-is-best-for-application-with/m-p/318457/

Good stuff to read there.