Does using a Bluetooth interface affect system latency the same way WIFI interfaces do??

As long as the driver is well behaved, it won't significantly raise the machine's DPC Latency.
BTW, you can get WiFi adapters with well behaved drivers (don't significantly raise DPC Latency).
If you're trying to run heavy loads at a 32-sample ASIO buffer size, I'd still disable WiFi.

Thanks Jim!  Your expertise is greatly appreciated!!

Another point with Wi-Fi is that the dominant latency issue is in Windows itself... "Auto Network Discovery" is enabled by default on machines, and pings every 3-4 seconds. That process should be disabled on machines (even non-DAWs) and if you connect to another machine, it should be a manual process, not automatic. I have not used BT enough to know if a similar "auto detect" function exists, my experience has always been to manually pair things.
 
Another latency issue is any program with an "auto-update" embedded into it... these should be set to manual start for similar reasons. Any open connection will prompt these to also ping in the background, which is another reason why "internet connection" gets a bad rap. I am not sure if such programs would try to use a BT connection, but is another thing to keep in mind.
 
Both of the above relate to machine setup rather than the connection itself.

I hate to be the bearer of less than stellar news here. If I were going into wireless big time I would be looking at a Mac. Actually for large midi stage presence I would do that even if not using bluetooth. I'm not impressed with windows wireless midi solutions. Apple's midi protocol works better than Windows presently. Lower latencies, more reliable hookups. 

If you're talking about Apple WiFi:
When pushing the heaviest of loads at the smallest audio buffer sizes, you still want to disable it.  
 
We have the top end MacBook Pro here (to support Mac clients who use VE Pro).
Apple WiFi isn't any different than WiFi on a PC (where the drivers are well-behaved).