1. You are entitled to withhold(v) that information.
    1a. You are entitled to withholding(g) that information.
  2. Full-time employees are entitled to receive[v] health insurance.
    2a. Full-time employees are entitled to receiving[g] health insurance.
  3. You will be entitled to your pension(n) when you reach 65.
    Please check, correct and comment.

1a and 2a are incorrect. You cannot use ‘to’ with the gerund form there.
Some people from Asian/Indian areas would probably be happy with ‘to be’ plus the gerund, but I wouldn’t find that natural either. It would sounds like ‘Indian English’ to me.