Fernco to ABS P Trap - questions

[MrFinPgh]

After having a plumber come out to fix my last issue, I'm back with a couple more questions:

The plumber removed the old tee to the DWV and put in a new tee with two fernco fittings. I think he also glued a threaded adapter at the end. See this:

However, I have two issues happening:

1) I've realized that the threaded part sits behind where there will eventually be a wall. I assume that's not ideal, so how best to handle? Is there an escutcheon i can plan on using? Or do I just plaster the pipe in place?

2) I'm not sure how to actually attach the p-trap to the fitting. The plumber left me with a host of parts, but I don't have a clear idea of what goes where, nor can I find a diagram. It seems like I have some kind of coupling that is also male threaded, but there's no female thread on the other side (what I would have thought there would be.. it fits loosely over the male threaded piece attached to the actual drain.

Anyone care to explain to me the right way to do this, or point me in the direction of a clear explanation of how it ought to be done?

 

[hj]

If that adapter is glued in, then he did NOT do you any favors, because the slip nut on the trap has to scrw on to it, and if it is behind the wall surface that can be difficult. Normally, you would glue a piece of pipe into the tee and then use that adapter you have on the trap to attach the trap to it. Black all rubber Ferncos are NOT allowed inside the wall, and those gray ones even less so. There are for connections outside the wall if they are going to be used for anything. At least it will be easy to take the tee out and redo it properly.