Firstly, whether they accept you or not, you and your child is having all the rights in your husband's property (ancestral or self occupied).
Secondly, if your husband is having only self occupied, and he has made will also then you might not get anything.
Thirdly, it is how you have brought him in regard to the religion till the time he he does not attain the age of majority as after that he has all right to chose his religion.
Lastly, but in regard to the caste you have all right to put yours on him. If he wants to take advantage then good for him in future and if not then it's his choice. But yes you can put for sure.