Thanks for all the helpful response.
Yes, they are both adorable! Although they don't like to be hugged or put on lap, they are very good companion and playful. I love them no matter which breed they are.
The reason I think they are NFC because of their weight is much less for Maine Coon even for female. I know their parents are on the big side. The tabby one has very solid bone structure. But I guess, domestic long hair cat is good too. LOL