As part of an interfaith church, the underlying fact is that we all come into it with different beliefs, ideas and opinions. This is part of the "deal": before we sign up, the information provided tells us that people of all beliefs are welcome. This gives all of us the need and responsibility to perform a balancing-act that usually doesn't exist in single-faith religious groups; all the more so as we are all ministers.
Here is the issue: not only do beliefs differ, but so do many practices and priorities. One major point of contention for millennia has been that certain religions mandate or encourage proselytizing (bringing new people into the faith in question) and preaching toward that goal, while others do not do this, and some explicitly forbid outsiders from joining. These differences create significant, and often provocative, differences in the mood of religious discourse by members and especially clergy of the various faiths.
We can see these differences in the ULC, especially in our social networking website. Not only are there differences in mood - even though those from proselytizing faiths do seem to generally refrain from direct proselytizing here, they seem to post much more actively, among the small number of active participants, than others.
Both "sides" are legitimate, but in interfaith settings, it's necessary to coexist with these differences. We all have the right to share and discuss our beliefs and why we hold them. But we also need to respect each other's rights in the same matter. We also need to have due consideration for each other so that we can coexist peaceably.
What may make it more difficult is that some differences may be irreconcilable, and some may be irritating to others. Here is where the need of balance really comes in. We certainly should avoid deliberately irritating or offending each other; but we also have the right to express our own beliefs, and that may include disagreements with the beliefs of others here.
I would suggest a couple of basic ways to keep a healthy balance and a strong community. One is to take as a condition of an interfaith community that we agree to disagree. As such, in our discussions, when we may argue a point, we should let it go if a brief exchange doesn't result in either side accepting the other. A few weeks before I write this, there came to the site a new minister, who posted an introduction including mention of formerly practicing Western ceremonial magic (occultism) but having stopped and become Christian. Having a history in such occultism myself, I felt obliged to mention that many occultists have considered themselves pious Christians, some being clergy, and some orders requiring members to be Christian. Our new fellow minister was adamant in his belief that the occultism and Christianity are incompatible. I did not press the argument further; we both fulfilled our moral obligation to state our belief without leaving others with no awareness that there is more than one view. Stopping there serves our fellow ministers, whereas arguing further would risk harming our community.
Next, using courtesy can do much to avert or defuse tensions. When we have to express disagreements, we should try to do politely and with consideration for the other. Similarly, it's important to try to be mindful of the interfaith nature of our audience here when we post, remembering that we differ from each other, sometimes even in the most basic assumptions. Perhaps most importantly, it's important to try to avoid taking a supremacist stance in regard to our religions. If you preach to a congregation of your believers, go right ahead; but in this venue of our interfaith church, we are not each other's followers, we are fellow clergy of other beliefs.
This leads me to a related question: can we "preach" here? I would in fact encourage it, under such considerations as above, though. This site gives us a great place to practice expressing our though and beliefs. Some of us may have to give sermons, for example, and we could help each other to improve in writing them, if desired. (I would suggest in light of the above, if we share a writing that is really aimed at an audience of believers in our own tradition, we start with a disclaimer stating that. This may avoid some of our brothers and sisters other sibs from feeling preached AT.
The needed balance again is between our right and responsibility to express our own beliefs and the need to be considerate of each other's beliefs, thus maintaining a strong interfaith community.