Potty training

K8

My son turned 2 back in Feb. Since then he has had nappy free time most evenings and an odd wee here and there. I m due a baby next month so initially thought I would wait till July August time to potty train him but so many friends told me he was ready so last Friday I decided to give it a go. He has done amazing however first 2 days he wore pants but wet them 3 times in n hour-twice whilst talking to me so we scrapped the pants and hes only had 1 wee accident but has also managed to poo on the potty as well! He loves the yogurt raisins and stickers he gets as a treat! He will wear a nappy when we go outside the house and for nap and bedtime.

How can I solve the pants issue though? Should I stick with brief pants or boxer shorts. He struggled to pull them down so definitely needs practice.