So, my suggestions resolved your first issue yes?
I'm not 100% clear on what you're asking in the next point.
However, if you're asking can you use two VLANs with one SSID, then yes. You simply add both VLAN numbers to the VAP profile. And then there further ways to configure it, depending on what you're trying to achieve.
I'm not sure of the significance of the 2 servers you mentioned. What servers? Doing what? Are these relevant to your configurations?
If you have 2 VLANs in a VAP, the clients are put into either one based on a hash of their mac address (so you should think of this as random). This is partially load-balanced, but it's not 100% predictable. There are other ways to do things, but you need to clearly layout your objectives, constraints and solution scale to work out what's best.
In terms of "vlan response time", how would you envisage measuring this?