"Host Wildcards can be used only for players outside the Top 30 of the ITTF TTWR. WTT Nominations are excluded from the WTT Feeder Series Play Down Restriction Rule." 

However, there are only two (2) available WTT Nomination slots for each Feeder event. The problem is that in the USA WTT Feeder events, there were three (3) Top 30 Players who initially applied: Mima Ito, Cheng I-Ching, and Chen Szu-Yu. WTT opted to give their (2) WTT Nomination slots to CIC and CSY, so Ito couldn't enter the singles event as there were no more WTT Nominations available. I made this inference because when the initial singles player list was released for the Feeder Events, the names of Ito, CIC, and CSY were all not listed. However, Ito and CSY were already listed in the Mixed Doubles event while CIC was listed in the Women's Doubles event. I checked the entry list a few hours later and CSY and CIC were suddenly listed in the singles event, but Ito's name was still absent, so one can infer that CIC and CSY got the WTT Nominations since after all, WTT Nominations can only be handed out AFTER the initial entry list is made. 

The next day, when I checked the entry lists again, Ito and Uda had canceled their Mixed Doubles entry. The likely reason is that Ito and most professional players won't be willing to travel to the other side of the world to play ONLY DOUBLES. It's highly probable that if either CIC or CSY wouldn't have gotten the WTT Nomination to play singles, they would have canceled their doubles entry as well. Traveling from East Asia to the USA just to play ONLY doubles in a lower-tier event isn't worth the time and effort. 

If Ito had been allowed to play singles in the WTT Feeder events, the Uda/Ito pairing would have likely pushed through, and Ito would have "unretired" from Mixed Doubles. It's a decision that was likely influenced by her recent losses. She may have wanted to play Feeder Tournaments in an attempt to "get back in form" and agreed to start playing Mixed Doubles again to give her an additional safety net to be chosen as the 3rd member for the 2024 Paris Olympics. She's trailing in the Paris Singles Points Race and missing the Olympic Singles event is a legitimate possibility for her. However, if her pairing with Uda proves promising, it gives JTTA extra incentive to choose her as the 3rd Olympic member (just like how JTTA chose Mizutani as the 3rd Olympic team member in 2020, primarily with XD in mind even if a lefty/lefty doubles combination with Niwa was not ideal for the team event).