In order to do forgiveness meditation, reflection on Equanimity and Kamma may not be so skillful. It really depends on how you're reflecting on Kamma and how you're reflecting on Equanimity.
In order to do forgiveness meditation we need to look at our actions. If we saw that our actions brought unbeneficial results and Dukkha, for ourselves and others, then we need to bring up Moral Shame, which is an unpleasant spiritual feeling. By feeling Moral Shame, it brings about a wise regret, and a wish, and a determination, to not do the unskillful action again in the future.
If we reflect on Equanimity in an unskillful way, we may get into thinking, "Oh well, you know, cause and effect, it all just happened due to my past Kamma and I'm stuck in it." So it really depends on how you're reflecting on Kamma and how you're reflecting on Equanimity that will determine if it is skillful or not.
After you become aware of the regret, it may be very helpful to examine what caused you to do such an unskillful thing, what ignorance in the mind caused you to do that?. If we reflect in this way, we are looking more into the Four Noble Truths, and into Cause and Effect in a skillful way.
Reflect on the Four Noble Truths. This Dukkha, how did it come to be? Did I have ignorance in the mind? Which hindrance did I have in the mind? Did I have an understanding of how to avoid this at that time? Then compare the person you were in the past with who you are now, seeing if there is any difference between your previous understanding and your new understanding. By reflecting in this way you start to get an insight into the changing nature of ourselves.
If you see there is a difference in your new understanding, it's more easy to forgive the person who you were. And if you don't want to do that unskillful action again, it's much easier to forgive the person who you were. You feel compassion for the person who had that ignorance which caused that unskillful action to arise, which caused suffering for themselves and others. You see that you don't expect the person who you were to have the same understanding that you have now. You see that they were ignorant, and then it's much easier to forgive the person who you were at that moment, and forgive the person you are now in the same way.
There is also a difference between forgiving others internally and forgiving others externally in a verbal way. We have to be very careful about this. We have to bring some wisdom behind our wish to forgive others. The reason for this is because if that person hasn't shown any regret for what they did, then it can be dangerous for them, and for others, if you express forgiveness to them verbally. If they haven't seen that their action was unskillful, then they haven't developed a healthy feeling of regret. So by forgiving them, they may start to think that their unskillful action is ok and that it's ok if they do it again. If they get forgiven without seeing any unbeneficial results of their unskillful action, it would not actually be showing compassion to them to express forgiveness before they understand that it caused suffering.
However, we can forgive them within ourselves by seeing the ignorance that caused them to do the unskillful action, which caused suffering for us and others. We can forgive their ignorance within ourselves so that we don't suffer. But through compassion to them and ourselves, we don't express that forgiveness to them, until they have understood the unskillfulness of their actions and show some regret.