The only way to do this in XSL FO is to use page templates for the last page and put that content in the region-after. There is no structure that yields a "rubber-banding" effect to push the content to the bottom, nor does float="bottom" exist (which would not work in your case anyway if it dod not fit, it would float to the bottom of the second page. You would use something like this from another project I have done.
<fo:layout-master-set>
<!-- ============== simple-page-master ============ -->
<fo:simple-page-master master-name="simple-page-master.only" page-height="792pt" page-width="612pt">
<fo:region-body margin-top="4.15in" margin-right="0.25in" margin-bottom="2.6in" margin-left="0.25in" />
<fo:region-before extent="792pt" region-name="region-before.only"/>
</fo:simple-page-master>
<!-- ============== simple-page-master ============ -->
<fo:simple-page-master master-name="simple-page-master.first" page-height="792pt" page-width="612pt">
<fo:region-body margin-top="4.15in" margin-right="0.25in" margin-bottom="2.6in" margin-left="0.25in" />
<fo:region-before extent="792pt" region-name="region-before.first"/>
</fo:simple-page-master>
<!-- ============== simple-page-master ============ -->
<fo:simple-page-master master-name="simple-page-master.rest" page-height="792pt" page-width="612pt">
<fo:region-body margin-top="0.8in" margin-right="0.25in" margin-bottom="0.64in" margin-left="0.25in" />
<fo:region-before extent="792pt" region-name="region-before.rest"/>
</fo:simple-page-master>
<!-- ============== simple-page-master ============ -->
<fo:simple-page-master master-name="simple-page-master.last" page-height="792pt" page-width="612pt">
<fo:region-body margin-top="0.8in" margin-right="0.25in" margin-bottom="2.58in" margin-left="0.25in" />
<fo:region-before extent="792pt" region-name="region-before.last"/>
</fo:simple-page-master>
<!-- ============== page-sequence-master ============ -->
<fo:page-sequence-master master-name="page-sequence-master">
<fo:repeatable-page-master-alternatives maximum-repeats="no-limit">
<fo:conditional-page-master-reference master-reference="simple-page-master.last" blank-or-not-blank="blank" />
<fo:conditional-page-master-reference master-reference="simple-page-master.only" page-position="only" />
<fo:conditional-page-master-reference master-reference="simple-page-master.first" page-position="first" />
<fo:conditional-page-master-reference master-reference="simple-page-master.last" page-position="last" />
<fo:conditional-page-master-reference master-reference="simple-page-master.rest" page-position="rest" />
</fo:repeatable-page-master-alternatives>
</fo:page-sequence-master>
</fo:layout-master-set>
This creates templates for pages that are first, rest, last and a special one of only (where first is last). You then output that content you wish at the bottom of the page into the appropriate regions (both region-before.only and region-before.last).
The only caveat/trick is if you choose different sizes of page layout to accommodate the information you want at the bottom, then you should make sure the last few rows of the inside of your table are kept together to pull a few of those rows to the second page.