Actually:

1. There are plenty of people who undergo the DIY method of enema. You can easily search the web for many such cases. There are medical studies with patients being required to self-administer home FMTs via enema. For example, this one, with 100% success rate: http://www.ncbi.nlm.nih.gov/pubmed/20117243. Some studies even include self-administered home enema as part of the continuing methodology, initially using a colonoscopy. There have been no recorded cases of infection and certainly not death.

2. There are multiple methods used for transplantation in clinical setting, the most common being colonoscopy and the second being nasoduodenal. I've read most or almost all the studies to date but haven't read a single one using the method you note, though it may have been the case. But it is certainly not the only one or in any way the most common. See here, for example:http://www.hopkinsmedicine.org/gastr...lantation.html.

3. FMT has been successfully studied in both Ulcerative Colitis and C dif., and from what I've heard out of Europe studies are being conducted or will be for other IBDs. You can Google and find many clinical studies.

4. The statement "messing with gut bacteria would not address it [i.e., an autoimmune issue]" has no evidence to support it, and in fact seems to fly in the face of the fact that 70% or so, as they say, of our immune system is in the gut. For my part, I just don't know, maybe it will, maybe it won't. I have no evidence in either direction, but I will note that so far it has reversed immune and/or inflammatory issues relating to the gut directly with astronomically positive results, 90% and higher.