Personally I would stick with what you have - the Level Term Policies on the rented properties are good. You shouldn't be advised to Consolidate as unless the terms of the mortgage are the same then you couldn't consolidate anyway as the terms on the policy would not match the terms on the mortgage.
With regards to the individual policies on the joint house - personally I would leave the policies as they are - you will probably find that there is not much difference in cost in having a joint policy versus a 2x single policies and with 2x single policies you would still have one in force should there be a claim.
Is Critical Illness worth the extra payment - I would say yes. I would always recommend a client to take out the Critical Illness as long as they can afford it.