If the baby doesn't burp after every feed that's okay just keep the baby in upright position for some time. And spitting of little milk and curdled milk is fine. It happens with small babies.

Yes dear..also after burping try to keep him on your shoulders for 10-15 mins after feed

Yes he can vomit out fresh milk.; burping is very important. Read these--<font color ="#3b5998"><b><a href="http://app.babychakra.com/article/2938">Is Your Baby Ready For Burping?</a></b></font> <font color ="#3b5998"><b><a href="http://app.babychakra.com/article/1074">How should you Burp your Baby?</a></b></font>