I Found A Second Slide

I found another slide of the family gathering at Grandma Hayes's house.  I am pretty sure it is the same day as this slide was also red and I think the clothing matches.   Here is my identification of the people in the photo, from left to right:  Carla in chair, Penny behind sitting on Sharon?  Wanda, Wendy with Tim behind on the piano bench.  Keith, MB, Karen holding Heidi, Merlene, Janet holding Paula and Howard.  My guess for the year is 1960 or 1961 as Heidi was born in July 1959.  Since there are short sleeves I wonder if this is Easter?  another warmer weather gathering?  Karen, Wanda, Carla, do you remember this?