I would hope that Hussites would simply be a flavor variant of Protestants, or even just regular Protestants. I worry that they'll be a separate religion despite literally just being premature Protestants that got squashed.
There is a reason Luther said "We are all Hussites". Indeed, Luther had stumbled across a work of the famously condemned Hus and read it favorably even in the very earliest years of his formation.
Source:
https://reformedreader.wordpress.com/2018/11/01/we-are-all-hussites-luther/
There is simply not enough difference between Hussites and Protestants to merit treating them separately.
Honestly, there's enough of a linear flow from Wycliffe to Hus to Luther that I'd even be okay with Lollard heretics in the early game creating Protestantism in England. From a game balance side it could cause some problems, with maybe Church Power not being activated until the Age of Reformation to avoid the early game military boost advantage. But from a roleplay standpoint it just makes sense.