Flaxen or something else?

I own a solid paint filly, registered as a breedingstock,has two little front stocks and two rear,snip and a little star,obviously sorrel. But I ve noticed a lot of white hairs in her coat,plus now the last inch of her mane is growing with a lot of white,not cream or red but white hair. His tail is reddish and orange but inside is also cream,white, some grey and black.
I think she's a minimal sabino,has a little countershading and shades on her fronte legs like possible leg barrings.

What do you think?

Does she wear a rug?

Nope.
I've bougt her at the age of 1 and I've already noticed that the last hairs of the mane were lighter,they're shorter-just growing up
Saddle fits well...

Not flaxen, just chestnut. Chestnuts do have a tendency to have some white hairs sprinkled through, so I wouldn't think there is much more going on.