1. Can Convert deski to webi report using report conversion 
tool.
2.Iam not sure whether we have different types of 
connections while creating report using free hand sql.It 
will be always secured.

1. But not all the desk-I documents are converted to Web-I 
through Report conversion tool. If there is any feature 
which doesn't available in Web-I is present in the Desk-I 
report, then it will not be fully converted, but parially 
or not converted depending on the feature.

Connection type for free hand sql DP is Shared or Personal.