Hello. I have some answers to some of your concerns. I'm going to take the easier ones first, so this will sort of be backwards from what you asked.
As far as other sources / literature out there with conflicting opinions, this is not all that surprising, at least, its not all that surprising to me. Without knowing who, or what, might be behind these other opinions, it is not easy to counter or debate them - even in the spirit of support, even if these other sources appear to be true proponents of natural remedies. On the one hand, it is really nice when we have our own first hand experiences to guide us. On the other hand, we can't all know everything from first hand experience, and as such most of us are often left in a position - eligible and or vulnerable, to consider ... or perhaps follow, what somebody else tells us. For somewhere between 20 and 30 years, Richard Schulze has been telling us to consider the results he's seen first hand... such as, that the herbal colon formula will not damage the colon but will nourish it, make it stronger, and as a result it will help to improve the health of other body sub-systems that depend on a healthy colon. But, if I was worried that a colon formula was causing damage to my intestines, and I was trying to tackle this concern solely from my first hand experiences, I would need to know what damage, if any, had already been done to my intestines before I decided to begin taking an herbal colon formula. In my opinion, the Schulze #1 formula will not damage your intestines, but it is ultimately up to you to reconcile this opinion with another to the contrary.
It was about 4 years ago that I first began taking an herbal formula for colon cleansing. This was not the Schulze brand but it was one made with similar ingredients by an herbalist also trained by the Christopher school and it included Senna, Cascara Segrada and Capsicum species "hot" peppers. It did not happen all the time but there were times I experienced mild heartburn-like symptoms.
Heartburn is a symptom that I've dealt with on and off for close to 20 years. In that time, which the early parts of were well before I ever stumbled on to the idea of natural / herbal remedies, I had experienced a fairly wide range of severity to these symptoms that when really bad, this went on for 48 hours or more un-ended, and spawned other symptoms (radiating pains, shortness of breath etc) in addition to the telltale, awful, nasty burning sensation all the way through the upper GI to the back of the throat. Just pointing this out to say that I know what severe heartburn symptoms are like. I'm also pointing this out to be clear that I'd been experiencing this kind of symptom long before I ever took an herbal colon formula for the very first time. If I was to refer to all of nasty stuff as one symptom "heartburn", by comparison, the times this symptom occurred after taking a colon formula were mild; some hot sensation in the stomach that lasted about an hour or two. I eventually discovered that if I took the formula just before eating a meal, the symptoms did not occur. If I took them after the last bite of food had been swallowed, they might occur. If I took them on an empty stomach, they would usually occur. Since I've switched to the Schulze formula, these symptoms have not happened. For reasons I have not figured out, I've gotten better results taking less of the Schulze formula. Before I was taking upwards to 7 capsules. So far I've never had to take more than 2 of the Schulze formula. This gets to the situation where it is often misleading to attempt arriving at valid conclusions based on comparisons between 2 different people seemingly being affected by the same cause; colon formula. In my case, I've got comparisons between 2 different formulas (nearly identical) seemingly causing different results inside the same person. If I was to use the simple method of cause & effect that I've been raised / conditioned to use, I might try to blame this situation on the one formula... I might, but I won't, because I have realized that there are too many other things going on inside me to make this a fair, legitimate comparison.
Heartburn symptoms might well be a sign that other things are going on inside one person, unawares, that are not going on inside the other person, unawares. It might seem the most logical thing to do is to stop taking the colon formula. In the short term, this might be a really good idea, but this then leaves another question; the longer term. Just keep in mind that the Schulze regimen on the overall is thorough, is demanding, the colon formula is just one piece of a many-piece orchestra. Over his time (20-plus years) he has publicly claimed the kinds of amazing success stories that no other person - orthodox or alternative, has publicly claimed. His colon formula is just one piece of a much larger program. Generally speaking, he is not the kind of teacher who will entertain people who might (operative word) be picking and choosing single pieces of his overall regimen they want to follow while shunning other pieces. It would be nice to say that we still live in times that freely allow a Richard Schulze to come here and advise you in person without the need to fear for his own life as a result. This is just a prominent reality among the countless realities we must consider. In the mean time, there are various other people who frequent this forum and often have good advice based upon real-life situations, so lets hope some of them come by with some good guidance for you. Good luck!