1a. yes games/projects created in v3.x will be compatible with v4.x
1b. freeware version does not allow compiling of .exe files but projects made in freeware version will work in licensed versions of Visionaire Studio.
2. currently no, but there will be; when v4.0 is released I should assume.
3. yes there will still be a €35 license option for the 4.x series which will/should allow you to compile .exe files for windows, mac & linux (possibly) albeit I'm hoping that we will have some new license options available for anyone wanting to purchase commercial licenses for their game.
Sorry in advance if you don't know much English
( I always reply in English)