"Ocoeur" is the alias of French musician Franck Zaragoza. It is, as you point out, derived from the French "au coeur". Since there is nothing on 
[his biog page](https://n5md.com/artist/Ocoeur) to indicate any other pronounciation, it is most likely pronounced as the French "au coeur".

Edit: 25th August 2020 : for 'Saycet' answer to correct/amend my own answer and include additional information provided in answer by @Bebs  (thanks!):
"Saycet" is an alias of French musician Pierre Lefeuvre and his collaborators.  His [fan website](http://saycet.org/biographie/) gives no clue as to the pronunciation, so I as a non-native French speaker assumed the final "t" is silent (like "ballet", "beignet", "Manet" etc). However, Google Translate has it with a sounded final "t" : as do the 2 interviews in @Bebs' answer : [interview 1](https://youtu.be/CZw9mzuNOFA?t=19) [interview 2](https://youtu.be/9nhvxPblgeI?t=160)- so the "c" is soft and the final "t" is sounded. 

"El Huervo" is the name used by Swedish artist [Niklas Åkerblad](https://en.wikipedia.org/wiki/Niklas_%C3%85kerblad) for his musical work. 
It probably dates from his involvement with the soundtrack to video shooter game ["Hotline Miami"](https://en.wikipedia.org/wiki/Hotline_Miami).His [website](http://elhuervo.tumblr.com/) has many South/Central American / Latin influences, so it's safe to say that it would be pronounced as Spanish: "el Huervo"