EVAL-ADE7880EBZ, Questions on current transformers


I am testing the EVAL-ADE7880EBZ and I have some questions about the use of current transformers: 

1. First of all, for the calculation of R1/R2 resistors (burden resistors), when we talk about "Ifs", we are talking about the current max measured at the primary level? Correct?

2. For example, I would like to measure signals up to 5Ams, I currently only have current transformers with me that convert 100/5A. Are they too big, so they won't be good for my application, or can they still be used? (Model: ASK 31.4, 100/50A, 2.5VA, 0.2 accuracy class). If it is not good, can you tell me some current transformers to use for my application (with relatively good accuracy)

3. On my current transformer it says 2.5VA, does this mean that the secondaryside is already 0.1 Ohm (R*i'^2) or is it something else?

Thank you in advance and best regards,