Sorry for the late response.
What you want to do with the QRTEngine should definitely be possible. I’ll answer your question in order :).
Question 1: Yes
Question 3: I’m not sure what you mean by this. You can use the Loop & Merge to “pipe” in text to your stimuli (such as the sentence text). The stimulus data as such can be managed in a spreadsheet editor (Excel, google spreadsheet) and then copy pasted into the Loop & Merge spreadsheet.
Question 4: We strongly advise you to do so, as the QRTEngine has been made with that specific design pattern in mind. You can only get one trial per run through a block and Loop & Merge allows you to repeat blocks a set amount of times.
We hope this helps, if you have any remaining questions, do not hesitate to ask!