I like your choice of the pictures for the characters.
Real good choices.
I have a question though.
In "The Gift of Ilúvatar" there is not even hinted at Miriel being the mother of Isildur and Anàrion jet the Family tree of Elendils line suggests it.
Did I miss something?
Just asking ;)

It was implied, but I specifically didn't go into details. If you check when Isildur and Anárion are born, you will see that it occurred when Elendil was married to Míriel. I also had things like Míriel calling Isildur 'senya' which means 'my child' in Quenya. Its also why Míriel gave Mírwen the bracelet, and why Isildur is so angry with her. As the eldest, and ten years old when his parent's marriage dissolved, he would remember her, while Mírwen and Anárion were babies and would not.

It's for the children's sake too why Míriel and Elendil keep their parentage a secret. Míriel was going to tell her father about them when she explained about her marriage in 2219 (the same year Anárion was born!), but when she faced the king in his anger, Elendil stopped her from doing it. He was afraid that her father, as king, would declare them bastards, which would leave them in a precarious position and leave them unable to inherit anything. After Tar-Palatir died, Míriel would have had them all brought to the capitol and named Isildur her heir, but then Ar-Pharazon had his rebellion. After that, she and Elendil kept the children's true parentage secret for fear of what the Usurper would do if he found out about them.

This storyline will be explored in Though Wind Be in the West, which has flashbacks from Elendil's perspective.