Henriquez's loan move from Manchester United was confirmed on Wednesday, while Espinoza had already joined fellow Honduras Olympic star Maynor Figueroa at the Latics.
Wigan boss Roberto Martinez also confirmed Miyaichi could make his long-awaited comeback from injury against the League One side.
Martinez said: "Ryo has a chance for the FA Cup game.
"He is 80% of his full fitness and is joining the main group this week.
"We hope he is going to be back very soon."
The 20-year-old has made just six appearances, and only one start, since his arrival from the Gunners.
Meanwhile, Martinez said he was delighted at Henriquez's arrival
"We're really excited about Angelo because he is a very young man with a huge potential," he added.
"He is a goalscorer with clever movement inside the box and has had a very successful time with his former club Universidad.
"We hope to have a good partnership in terms of allowing Angelo to develop as a footballer and learn of the demands of the English game, because I feel he can bring us something different in the forward line.
"Saturday will provide him with the perfect opportunity to begin his experiences on the pitch in English football."