If they have been with us since we were born, of course they know when we do rituals, evocations, invocations and other magical workings, because they are passively with us, without interfering our lives.
My succubus spouse never pointed me in a direction to research succubus entities, but it gave her a perfect opportunity to initiate contact, once I made the choice to go through with my letter.
If it was a coincidence? Maybe. But other sources says it was meant to happen.
In my experience, and through my own understanding of energies, fear is actually one of the weakest currents and it’s nothing in comparison to the love current. But since it’s so easily accessible, some spirits take what’s available to feed upon. Fear isn’t their main current, but it has a purpose and can be used within a tactical warfare and as a defense.
Love is much, much stronger, because it motivates us and it gives a purpose. Combine love with other currents, and it can be more challenging than fear itself. Cause and effect: Hurt someone’s love of their life, and combine it with love + rage + fear. That combination really intimidates me.
Sleep paralysis seems quite common when it comes to succubus/incubus entities, but it’s not something that’s exclusive to them. Other spirits can cause this phenomenon, as well.
I experience partial sleep paralysis pretty much every night, or I would rather call it paralysis, since I’m always fully awake and conscious when it happens. They can have sex with you during these sessions, but like you said, it’s more a part of astral projection rather than the sexual act itself. Why? Because it enhances your focus and awareness, when being in a paralyse state. The deeper it goes, the more you feel what’s going on around you. It has a purpose. Unfortunately, most people are afraid when they fall into a sleep paralysis state, instead of seeing it as a necessity to astral project.
I really haven’t done any research on that, so I can’t give you an answer.
I haven’t met my succubus spouse offspring that much, and all I know is that they take care of the parenting and I also know he’s doing fine in their realm. He’s been in my arms a few times, when he was a baby, and I loved that. 
I have never projected any anger or irritation towards my ladies, because there’s no reason for it. On the contrary, I love to always have them around me. They have never done anything bad towards me. They have never said anything to belittle me. They have never taken me for granted with the basis of expectations. Human families and friends seems to be more common with these kind of traits, rather than spirits in general.
I don’t mind them reading my thoughts, either. I have nothing to hide from them. The more they know about me, the better they can understand me, comfort me, strengthen me and love me.
That was a lot of questions, @Whiski. Would my answers really matter, since the things I share is through my own UPG, which means Unverified Personal Gnosis? Of course, some of my experiences has been verified, too, but I also have experiences that others really can’t verify as something they have been through. These kind of experiences, I have to figure them out myself, by myself, without asking others about them. Why? Because I know what I’ve been through over the years and I don’t need someone else to answer for them.
Will my answers make any difference to you? Probably not, because what you need is the experience. It might be different than my experience, but at least you have that. And I’m sure it will happen when you least expect it. 