Looked. But...not all characters shown :(
Yes, on the preview, not all characters are shown, but most of the fonts that can be found with the link I gave you actually have the Lithuanian characters you're looking for. You should download one and try

Lithuanian disse 
... a) is close to authentic mediaeval ...
What do you consider "authentic mediaeval"?
Lithuanian have a look at Gilles le Corre's 1475 Bastarde Manual:
http://www.myfonts.com/fonts/glc/1475-bastarde-manual/
I am not sure but I think your Lithuanian characters are there. Hope this helps a bit.
Todos os horários são CEST. Agora são 19:45