i posted some leafhawk au fanart a few years ago, so here's what i think the three would've looked like if hawkfrost had been their father instead of crowfeather!
hollyleaf looks about the same aside from brown spotting here and there, as well as keeping her canon name (however a small running joke within thunderclan is that spiderleg is an unwilling dad yet again lmao)
jayfeather is the kit that looks the most like hawkfrost, and his name would either be frostfeather (like how leafpool wanted her kits subtly name them after crowfeather to acknowledge him as their dad) or frostbird!
lionblaze is given the eagle- prefix instead (hawks and eagles are both birds of prey ykyk) and seems like the perfect physical blend between tigerstar, brambleclaw, and tigerheart
the only things i can think of for my interpretation of the au is that the litter could be perceived as squirrelflight and brambleclaw's a little more palatable than the wild black + silver tabby + golden tabby coming from a ginger mother and brown tabby father from the canon lmao
the clan takes note of jaykit / frostkit looking a lot like hawkfrost and lionkit / eaglekit looking eerily like the first tigerstar, but it's merely brushed off as brambleclaw's genes being more dominant and try not to bring it up
hawkfrost DEFINITELY visits his sons in their dreams, but avoids his daughter for some reason i haven't concluded yet :/ also in my version of the au hollyleaf has dovewing's powers because why tf not
just had a tense day and trying to unwind with some Combat Cats™