Polish-mixes will typically have smaller crests than pure Polish.
The more crested chickens how have, the more your other hens should get used to seeing crests (so hopefully they will not pick on the crests as much.)
If you want to try hatching eggs, I would say to go for it-- I would not expect any big problems.
Definitely not monsters.
I do not personally have photos, but I have seen some posted in other threads.
https://www.backyardchickens.com/threads/my-giant-polish-mix.205040/
This thread shows a chick that is a mix of Polish with Jersey Giant. Yours might not be that color or exactly that size/shape, but it should give some idea what to expect: looks like a normal chicken, except with a bit of crest.
https://www.backyardchickens.com/threads/could-you-guys-post-some-polish-mix-breed-pictures.126949/
Here's another thread from quite a few years ago, that has some photos of Polish-mix chickens owned by several different people, mixing Polish with various other breeds.