The second row of pictures appears to show intermediate trophoblasts.  Too pale to be sure.  I would submit all the tissue and cut down all the blocks.  If still no chorionic villi or definite implantation site are seen, you report descriptively and communicate with clinician about the situation.  Make sure to ask the doc to monitor HCG level.  If this is product of conception in uterus, HCG level should drop quickly.

It is very difficult to diagnose intrauterine pregnancy by implantation site.  During my training days, i had used cytokeratin immunostain to confirm.  Intermediate trophoblasts should be CK positive.