1. This is sounding a be niche that won't fit will in a generic plugin survey plugin. We can't give everything away for free, as this is how we make our money.
2. Theoretically is is possible to put html in both the question and the options, but as any html is removed so that they can be stored correctly in the db it must also be accompanied some identifying text. This isn't exactly a feature its just something we haven't spent too much time on preventing.
3. We'll look into the responses. Was it all of them or just a few in particular?
This was tested, but nothing is 100%
4. Regarding the mandatory fields sticking, were they sticking on or off? also was it particularly any type?
Some types are forced to be mandatory, so as name,email or captcha.