It is known that Japanese names often have multiple readings depending on what reading (on'yomi, kun'yomi, nanori ...) is applied to each kanji.
But my question is about foreign names written in kanji phonetically.
When someone gains Japanese citizenship, they usually change their name from katakana to kanji (at least the given name or the surname).
Alessandro Santos 三都主 アレサンドロ （Santosu Aresandoro)
Sergio Escudero エスクデロ 競飛王 （Esukudero Seruhio)
Brendan Neilson ニールソン武蓮伝 （ニールソン ぶれんでん)
Wagner Lopes 呂比須 ワグナー （Ropesu Wagunā)
Martti Turunen 弦念 丸呈 （Tsurunen Marutei)
Seeing this, my question is if it is possible to mix the on'yomi and kun'yomi readings. I mean, can you choose the most suitable reading of a kanji (on'yomi or kun'yomi) to build each part of your name in kanji?
By example, Spanish footballer Sergio Escudero has this name: 競飛王 (Seruhio).
The first kanji 競 has Kun'yomi reading SERU But the second and the third kanji have the On'yomi readings HI and O respectively.
It makes me think that it is possible to choose the most convenient reading to write our foreign names in Kanji.
However, in the past, I read things like this..
https://thejapanesepage.com/forum/viewtopic.php?t=15189#p169635 (see the last post) ...stating that you can't mix the readings to write your foreign name in Kanji.
What do you know about this? Do you think it is possible to mix the readings?