Hi,
1.Why it has to be past perfect here (if it indeed has to it)?
The book is a good reference book. One teacher who had used the book in its original editional said this.
It doesn't have to be Past Perfect here, since the sequence is clear with just Simple Past. But Past Perfect just adds some emphasis.
2.Could we use many present tenses in situations like this? Yes, multiple uses are fine.
Today, he has been presented with a Certificate of Appreciation for his service to the community he lived in and has seen some friends he didn't see for a long time and has eaten great food at the banquet that followed the award ceremony.
Best wishes,Clive