Questions - hopefully with occasional answers! - is what we do here.
Welcome to the thread!
Out of interest, which estate ?
Edit : Seems like Simbithi down in KZN ?
Technically you are a "Gated Community" or "Lifestyle Community" and the service offering within the estate is one of those offered by Telkom's "Gated Community Services" (GCS) division.
Gated Community residents can usually choose between "line only" packages provided by Openserve (= Telkom Wholesale) and full-service "line + data" packages offered by Telkom Retail. Sounds like you have the latter.
That's all pretty standard, yes (see
here for comparison).
Sounds like you might have the ZyXEL SBG-3300-N000 fibre-ready router ?
Technically it is possible, yes - absolutely. Contractually you'd need to see what options your estate has negotiated with Openserve/Telkom, but it should also be possible, yes.
If you wanted to exit from your full-service (line+data) agreement with Openserve/Telkom, and enter into a "line-only" contract with them, that may be regarded as a contract downgrade and there may be some form of early-exit penalty.
At the moment, your line is provided by Openserve and you have a data package from Telkom Retail. Technically, nothing prevents you from having another data package from a different ISP (like WebAfrica).
Within an estate you generally have no choice but to use the
line service provider chosen by the estate - Openserve, in your case. But for the
data package you are usually free to go with any ISP who offers service over the Openserve fibre network.
Have a look at the various package options in
this post (pertaining to GCS in "The Wilds", Pretoria). Your options should be similar.
Correct, yes. If you have a WebAfrica data account, you will have a PPPoE login (username+password) with them. You can enter those PPPoE login details as a second WAN entry apart from the Telkom one that's already stored in your router. The only proviso is that you can only connect to one data provider at a time (I think).
It will work fine, yes. This is by virtue of an Openserve service called IPC (IP Connect) whereby participating ISPs - of which WebAfrica is one - can provide data services to any subscriber who is on one of the Openserve access networks (eg fibre or xDSL). If you can connect to a WA account from your Openserve fibre line then you have already confirmed this for yourself.