i) Notice that
∠QEB=∠QPB=∠QDA⟹∠QEX=∠QDX
So quadrilateral XDEQ is cyclic and similarly quadrilateral YCFQ is cyclic. Let S be the second intersection point of these two circles. It's clear that ∠QSX=∠QEB=∠QCY so X,S,Y are collinear. Let R′ be the second intersection point of the circumcircle of triangle DSC with line XY. We have
∠R′DC=∠R′SC=∠YSC=∠YFC=∠FAP=∠FDP=∠CDP
Similarly it's obtained that ∠R′CD=∠DCP. So R′ is the reflection of P onto CD, and so R≡R′. □

ii) It's easy to see that FR=FP=AD and RD=PD=AF. Thus AFRD is a parallelogram and therefore RD∥AF and RF∥AD. Hence,
RXRY=DXAD=DXPF
So the problem becomes equivalent to showing that RXRY=PXPY. Thus it suffices to show that PXPY=DXPF. Note that ∠ADP=∠AFP, so ∠PDX=∠PFY is enough to show that
DXPD=FPFY⟺FYAF=ADDX
From RD∥AF and RF∥AD both sides of the last equation are found to be equal to RYRX and hence the claim. □