I couldn't see any Chapter 10 and 11 in English but I saw both chapters in another language. I will be leaving it here for the moment to people who likes to see the pages.
Chapter 10:
https://qmanga.net/20-mensou-ni-onegai/chap-10_24432.html
Chapter 11:
https://qmanga.net/20-mensou-ni-onegai/chap-11_24431.html
These are the chapters that I can see. Apologies that I couldn't find the English version of this.
I think the manga is just only a teaser for the novel that they have. There are 3 volumes of this manga in the same title, even gaidens(?). Here is the link. https://www.alphapolis.co.jp/book/detail/1042830/454
When they climbed the tree to look at the World Tree who is carrying Cinq?
Akari and Mini Gran are sitting beside each other, clearly showing they are not carrying Cinq. An cannot be carrying Cinq as she is able to jump to Akari's head immediately. Deux is also not seen carrying Cinq in one panel after An jump on Akari's head. And the Twins are grabbing ahold of the unstable branch they are sitting on making me believe that it would be difficult to carry a younger brother at the same time...
Sorry for the long messege.
Summary: Cinq is not with them looking at the World Tree, where is he?
I wonder when Princess Princess Plus will be available...