Weblogic domain and cluster creation with WLST
There are two steps missed after the step 1, you need to copy the configuration from the machine where the AdminServer is running run to the other machine in the cluster using the command pack content in Weblogic installation:
1.1 On the machine where the AdminServer is running run ./pack.shdomain=/home/oracle/config/domains/my_domain
    -template=/home/oracle/my_domain.jar -template_name=remote_managed -managed=true
1.2 Go on the other machines and copy the jar file produced in the previous step  and run ./unpack.sh -domain=/home/oracle/config/domains/my_domain -template=/home/oracle/my_domain.jar SAML_IDP_FromScript
Now you have copied all the file you need to start the NodeManager and the ManagedServers on the other machines.
I want to create a cluster with 2 managed servers on 2 different physical machines.
I have following tasks to be performed (please correct me if I miss something)

Domain creation.
Set admin server properties and create AdminServer under SSL
Create logical machines for the physical ones
Create managed servers 
create cluster with the managed servers

I have following questions.

Which of the above mentioned tasks can be done offline if any ?
Which of the above mentioned tasks must also be performed on the 2nd physical machine ?