Bless Fiona! PAY ATTNETION! LOL
No, I don't think Martina could beat any top tenners to be honest. She is good in doubles and she was good in singles during her era but the top 20s may be just too good.
However, if I had to pick someone to beat Martina, I would definately choose Monica. It would be good for RG (in fact any GS) to have a retiring legend playing a legend instead of matching up a top player to beat (I know I know, there is always possibility that she beats them! But very slim nonetheless) Martina. It will attract more viewers anyway.
Just my $0.02