For the 2015 Speed Queen front load washer, selecting the Second Rinse adds one additional rinse cycle. Selecting the Third Rinse adds two additional rinse cycles. Selecting both Second and Third rinse options together will add three additional rinse cycles for a total for five rinse cycles.
As far as answering the second part of your question (rinse and spin with prewash and additional rinse), I will give it a try tonight and let you know tomorrow.
You can also shorten the wash cycle by choosing a lower Soil Level since the default soil level is Medium. For example in Heavy Duty mode you can cut your wash cycle down from 45 minutes to 40 minutes by selecting the Light soil level. The manual does not contain any information on how selecting the soil level changes the wash times. It only lists the wash times for the Medium soil level. Other levels, such as the Normal/Eco cycle will cut your wash time even more. I just don't know what that is but I will get back to you tomorrow with wash times for each cycle based on soil level selection.