Hello Jerome,
We're glad to hear you're making good use of the survey tool and thanks for your compliments. It's nice to know the work is appreciated.
Concerning your questions:
1. One of the limitations of v. 1.2.* is the fact that it is not possible to export the questions in other languages except for the default language. In Survey 2.0 this option has been added and now it's possible to export all language versions of a question at the same time.
2. There is no easy answer to this question. The first way to try would be to make use of the new data export and import features (formats Xml or csv) of Survey 2.0. You would have to export the answers from SP v. 1.2.* first (xml or csv). Export the survey from v. 1.2.3. and import it into v. 2.0. Next use the Survey 2.0 import feature to load the answers. The beta version still has a bug with the Cvs import/ export. Try the xml but you run into error messages or may need to manually correct the xml file.
Two tags you will have to add to the v. 1.2.3. xml files are:
<AnswerDisplayOrder>3</AnswerDisplayOrder>
<QuestionDisplayOrder>3</QuestionDisplayOrder>
To find the right order numbers you will need to query the database e.g.:
select * from vts_tbsurvey where surveyid = 133
select * from vts_tbquestion where surveyid = 133 and questionid = 425
select * from vts_tbanswer where questionid = 425
We will keep you updated on any easier solutions.