With the following typoscript I get all content from the subpages on one page:
lib.allPid = COA
lib.allPid {
10 = HMENU
10 {
special = direct
give a try to vhs ViewHelper it'll give you exact output what you want I mean default wrap and at all.
{namespace v=FluidTYPO3\Vhs\ViewHelpers}
<v:page.menu pageUid="2" includeSpacers="0" resolveExclude="1">
<f:for each="{menu}" as="contentList" iteration="Iteration">
<div id="uid{contentList.uid}" class="inner-page-content-of-pageUid-2">
<v:content.render column="0" pageUid="{contentList.uid}" />
</div>
</f:for>
</v:page.menu>
something more about vhs ViewHelper