I can only make comment about a recent install of Pulse in KDE, so take it as you wish as it may differ from your situation .....
When Pulse is correctly installed with the various other packages, such as volume control and device chooser etc etc the only option in the KDE multimedia section is Pulse.
The PCC tick box mentioned above does as you describe ...... seems redundant.
Pulse replaces OSS. I even went so far as to remove any OSS snd modules remaining .... but that was going a bit further than needed, and I did it to see if any app I use complained.
Kmix was no longer doing anything so I removed that also.EDIT:
Pulse Vol Ctrl is the only active one.
I figured out where I was going wrong and have Kmix operating again. Interesting ..... I Kmix vol control seems to control a portion of the full range ..... or something like that ..... I guess I had a misetting when I first tried it.
Alsamixer shows Pulse as the default sound card, with minimal adjustments.
It can display HDA Nvidia as another sound card ....... but I have not played with that at all. That has lots of adjusters.
My wecam Mic can also be displayed as another sound device
Anyway, I have not resorted to Alsamixer since installing Pulse.
I also have Xfce DE installed as an alternate to KDE4 and have no apparent problems there with Pulse. In fact it is even better as Xfce has a volume changing applet in the tray which I don't yet have in KDE4
The same Pulse controls with the same devices etc etc are available in Xfce.
It would appear Pulse is DE agnostic ....... or seems so by what I see here ....
It appears to me you have an incomplete install of Pulse.
I don't know if it can be corrected by installing any missing packages.
I have no problem using
Wireless headset ... including Mic
Mic plugged into the sound card
Sound over BlueTooth .... for the first time ever! I can even play music into the BT earpiece which is normally used with the phone!
My short experience - on only one PC - indicates to me that Pulse is an absolute marvel, but it does need to get installed properly, else things do not work as they should.
I know the above does not directly address your problem, but maybe something in there might give you some ideas.
As you are using Pulse then the more important (IMO) pics would be pics of the various tabs in Pulse Volume Control ...... particularly the Configuration Tab, which should show your Webcam Mic .... is it even turned on?