For the top, I think I would try making rounds of smaller shells, going down to 6 dc, then then etc
This reminds me of Haruhi's sweater from Ouran Host Club!
Baltic Baby Sweater PDF knitting pattern by frogginette on Etsy. Use a standard pattern - invert hem and make tabbies - easy.
Ravelry: Project Gallery for Cupid baby cardigan pattern by Melissa Schaschwary
Baby Boy Sweater 12 to 18 Month Size Wool by SilverMapleKnits
Ravelry: Temptation Poncho and Hat Set pattern by Tatsiana Matsiuk by rae