That's a straight comb (best I can tell). Cute birds.. I agree with possible crosses.
Single comb (aka straight) is recessive to all other types.. but two birds with other comb types (rose for example) could be carrying 1 gene for straight (hidden, the recessive part) and throw offspring with straight combs when mated together. Looks more like a Deleware cross to me with the barring (*if* that is what it is on the top back of the neck).. white skin being dominant to yellow (Deleware or columbian Rock would have yellow if pure).. but the feathers are very smutty or leaky.. just a description indicating crossed, not a judgement. The lack of yellow shanks and rose comb point away from columbian Wyandotte and closer to light sussex. I'm essentially throwing darts in the dark though..
See an example of rose comb and a few others in the following link..
https://blog.meyerhatchery.com/2020/10/types-of-chicken-combs/
Thanks for tagging me and sharing the pics!
Having a variety of eye candy is worth the not knowing, plus I love a good little mystery.
Sorry I'm not much help. Hopefully you will get more and better feedback.