For your first issue, I just discovered that some strings are hardcoded inside controllers! The ''Latest published stories'' is currently hardcoded inside StoryController.cs and if you are using the deployment package of v2.5 then you'll not be able to change
it. The only way currently is to Open the source code, modify your literals in this classes -it is used in several places- and then recompile the code.
For 2nd issue about view 1st frame, I don't know what is the reason! and actually I couldn't be able to see the issue. As I just opened the jojoot.nl and the video on the right display fine. and there is a snapshot of some video frame!
For the 3rd issue this is also a hard coded string in side Kigg.Web.DateTimeExtension class! It will require you to modify it and recompile.
for 4th issue, e-mail templates can be found under folder MailTemplates of your web. You can modify the text on those templates. but be aware of not to mess up with the placeholder that is used to be replaced with data fetched from kigg.
For the literal strings issues you mentioned you need just to upload the Kigg.Web.dll assembly as all changes will be inside this assembly.
I hope I was able to cover some of your needs. We want to support localization, but it might take sometime.