Carer Premium in mixed age couple

Client claims ESA (joint) and PIP DL, partner claims SP (but no PC). Mixed age couple.
Adult child lives with them and claims ESA and DLA mid Care.

Client has severe depression etc, and I’m taking extra care before advising as any complications or adverse reaction by DWP would likely have a very negative impact on the client.

Because of the partner neither client nor son gets SDP, but I’m considering Carer premiums in 2 eligible people’s benefits.
Pretty much just looking at which person would have the least difficulty claiming. Am I correct in thinking that:

1) Partner can’t claim Carer’s Addition, as while she might have an underlying entitlement to C Allowance, no current claim to PC means it cannot be applied.
Edit: Or could it be applied in the client’s joint ESA claim…?

2) Client and child can claim Carer Premiums for caring for each other, and can do so without claiming CA. 

3) Carer Premium can only be backdated as far as CA could have been - i.e. 3 months.

4) None of this prompts a CiC that would adversely affect the ESA awards, and the claims should be relatively straightforward.

[1] ESA could include a carer premium if the partner is entitled to CA, even though not actually in payment because partner is receiving State Retirement Pension
[2] No, they would have to each claim CA in order to be entitled to it (whether payable or not);  the condition for the carer premium in ESA is that a person is entitled to CA (with a “run on ” for 8 weeks after CA entitlement ceases)
[3] Following [2], the premium only starts with entitlement to CA
[4] Not sure what you mean by “adversely affects the ESA awards” - if either claimed CA and CA was awarded and put into payment (because no contribution based ESA to overlap with), then ESA award would be reduced but income overall (ESA + CA) would increase

Fair enough - I got confused by the wording that Carer Premium can be paid when you are just entitled to CA. Not sure how I was planning claiming CP without first claiming CA would work…

By ‘adversely effects’ I was looking for any common issues with this type of claim (like EUSS and HRT for instance). I have advised on a few CA claims in the past, but not one where I am this worried about the consequences of DWP muck-ups on the client’s mental health.