Fuynnybone – raw onion is shehakol. (according to some poskim)
The Nitei Gavriel states outright any “YereK” whose brocha is Borei Pri Haadama is acceptable except for those that re acceptable as maror.
Hilchos Pesach Vol II, Perek Pey Beis. Sif Daled
http://hebrewbooks.org/pdfpager.aspx?req=46448&st=&pgnum=404
Sif hey – Nohagin Lchatchila lachzor achar yerk hanikra Karpas.
Sif Vav – Petrozila Vyeish Omrim Celery
http://hebrewbooks.org/pdfpager.aspx?req=46448&st=&pgnum=405
Sif Zayin- Yeish Nahagu Likach minim acheirim
http://hebrewbooks.org/pdfpager.aspx?req=46448&st=&pgnum=406