I've heard of the Mark Lester connection for years, I actually think he may be the childs biological father. It clearly isn't MJ by any stretch, except possibly Blanket.
I don't know about the other two - but I can see some resemblance between Paris and Mark Lester. Very minor and tenuous - but they have the same shaped mouth and ears.
When I saw the kids at MJ's funeral, I thought that perhaps these kids were engineered to look white yet not pale - I doubted ML's story. At the funeral, Paris had the same skin tone as their aunts Janet and LaToya and that was very evident. Recently, when Paris is with her mother, or cheerleading etc, I can't help but notice how white her skin looks nowadays. Obviously they live in the California sun, fake tan is popular, skin bleaching is a Jackson family normality can all change skin tone,evening lighting or camera flash...it's just her skin looks different a lot of the time...but paler than when she was younger.
My two penny's worth is that ML might me Paris's biological father - but not the others, I think they all have different fathers.