LGL has made it pretty clear for a long time now he wants XX to focus on the various doubles events. It's not so much they are sending him in alot of events to deny him a single spot, as he's already pegged to carry the doubles.
That said, if Ma Long is still injured for the Olympics XX might still get that other singles spot, and still have to carry all the double events he's allowed to be in. Simply because they don't really have anyone else.
FZD already has the other spot, past that other choices are LGY, LJK and WCQ, none of whom are ideal.
LGY's psychological strength under pressure is still suspect the CNT will avoid giving him an Olympics spot like the plague, LJK has poor stylistic matchups against CNTs biggest threats, and WCQ is very inexperienced and unproven.
They just don't realistically have other options, they will likely go with slightly injured ML or very overworked XX.