MrsSB - if people can call their poor DC after places they were conceived, their favourite tipple at the bar, girlfriends of football teams - then I think your suggestions barely make it onto the stupidity ladder at all. Anyway, August has its own meaning: au·gust (ô-gst) adj. 1. Inspiring awe or admiration; majestic: the august presence of the monarch. See Synonyms at grand. 2. Venerable for reasons of age or high rank.
I wouldn't use Septimus if you paid me, although I do like Octavia.
Betty Draper from the TV show Mad Men is called January Jones in real life. I hadnt considered it before but I think it works quite well as a girls name.
So month names I would consider useable would be January, March, April, May, June, and October for girls and August for a boy. But I do think the child would need to be born in said month or it wouldnt work.
I don't mind month/holiday related names, but I'm not a fan of naming after the month they were born in, I think it's quite cheesy. Same for Valentine/a for those born in February or Holly for Christmas babies... August/a, June, May, etc are all names in their own right.