August is such a popular (and classic) name here so there wouldn't be any problems at all with him being born in December. I go back and forth on
August though, like you I prefer the look of it but I'm not completely in love with how it sounds. It keep popping up in my head whenever I think of other names possibilities for 'Eggbert' though.
Let us step into the night and pursue that flighty temptress, adventure.
PNL: http://www.behindthename.com/pnl/45898
Top: Alice and Matteol
Bottom: Kenzie and Deacon
'Eggbert' due December 2018