Will the non-colluding servers communicate in IT-PIR schemes ?
When the servers may collude then if they are all corrupted it's exactly the same as 1-server PIR. Thus, in information-theoretic PIR, it is always assumed that only some subset of the servers are corrupted. 

It is unclear to me what you would gain by running MPC between the servers. One possibility is to simulate a single-server PIR with many servers. But this would just cost more.