I know of three lists of Saul's children:
1 Samuel 14:49 - Saul’s sons were Jonathan, Ishvi and Malki-Shua. The name of his older daughter was Merab, and that of the younger was Michal.
1 Samuel 31:2 - The Philistines followed hard after Saul and his sons, and they killed Saul's sons Jonathan, Abinadab, and Malchishua.
1 Chronicles 8:33 - Ner was the father of Kish, Kish the father of Saul, and Saul the father of Jonathan, Malki-Shua, Abinadab and Esh-Baal.
The second list causes no problems, as it's not esclusory, listing only those sons of Saul who died in battle. The first and second list, however, appear to contradict each other. Eshba'al(Ishbosheth) is missing from the first list. Perhaps you could say that Saul's sons by his concubines, Armoni and Mephibosheth, were born after this list's creation, but the same cannot be done for Eshba'al, as we know he was between 35 and 40 at Saul's death(2 Samuel 2:10).