Quick question about under clothes?

Need opinions of if this is too hot or okay



IF I decide to have my son wear his bear costume ( which is really a winter over thing that zips up)

would it be too much to have him wear thin long sleeve pjs underneath
or
should i just have him in a onesie?


I tried it on him today with just a onesie and he was fairly warm in it with in about 15-20 min But we were inside not outside,

we will be outside around 6pm-8pm which accrouding to weather channel it will feel like about 60 degrees outside. as a high , low about mid 50s

babys need one more layer then what you are comfortable in....so if you are fine with a short sleeved shirt and a light sweater he is fine with the short sleeved shirt under the thick bear zip up

I think just a simple onesie and socks should be okay..(underneath)