Folklore-question

[pengolodh_sc at yahoo.no]

Can any of you guys explain a bit about the following folkloristic 
vermin and critters:

Poltersprites
House lutins
Duende
Nisken
Servan
Follets
Psikies
Kobolds
Linchetto
Opinicus

And can a brownie turn into a boggart (not in HP; in folklore-
tradition)?

Best regards
Christian Stubø

"Oh, what did you get 
that mare clipped for?
She looks so thin and old!
What did you get 
that mare clipped for?
She'll surely catch a cold!  

I'll sit down at the table 
and I'll let my temper cool...
I've been married to you these fourty years
and you're only a born fool"
CASTLE WAITING - VOLUME I:  The Lucky Road, by Linda Medley