That link didn't help much but I'm gonna say pretty confidently, yes that's a lie.

WARNING FFX SPOILERS:



Aeris is half Cetra, so given they aren't even IN Spira then that rule her being Yuna's descendant out.
The continents are too different for any hope of tracing their past anyway, that's a hell of a long time reforming.
Given any descendent of Jecht would almost certainly be a descendent of Tidus' this not being mentioned would probably be a hint that it was made up.

Why am I even giving serious arguements here? Does the article say that Nanaki is a descendant of Kimhari too?