Thanks again everyone! Sure am learning alot about the "do's and don'ts" in regards to this whole plumbing experience! Really appreciate all the feedback I've been given!
I'm really surprised to know that the slip joints shouldn't have been used (due to the possiblity of leaking). Guess we just figured it could be installed much like the drains you might find under a sink? Like I mentioned, we did this over 7 years ago and haven't had any problems with it. Guess we should consider ourselves lucky in that respect!
All of that old plumbing setup will eventually all be removed when the new plumbing is installed (hopefully within the next month) so will be keeping our fingers crossed that it doesn't start leaking before then.
Thank you too, Liquid, for your very descriptive response on what we need to do/use. I do have a couple of questions though, if you wouldn't mind answering?
1) Does it matter where the location of 3" vent line is placed on the drain line?
2) Does it need to go before or after the toilet drain?
3) What do you mean by "vent the bathroom group with a 2" wet vent up to the lav takeoff" What is a lav takeoff?
4) I know this may be alot to ask, but could you possibly draw some type of a diagram for me so I can fully understand the layout you are describing?
I really wish we could afford to have this done professionally, but unfortunately our funds are rapidly depleting (due to other unexpected financial needs).
Think I may also go to the public library and see if I can find any information on some of this (especially to maybe learn the different parts of the draining system--i.e, sanitary t's, wye's, elbows, etc.)
I truly do appreciate the help I've been given!