How many products am I selling?
You said it's all one product, so I assume you know better than me. LimeLM doesn't force you to create other products if you're just selling the licenses under different models.
What plan that you offers fits this model and what is the best way to implement.
The "Plus plan" (or above) best fits your needs because you'll be selling "Network licenses" (floating licenses).
I plan to use FASTSPRING, so I can list all my products there with the appropriate scripts. How will LimeLM issue the correct number of activations based on the above examples.
Well, we have an article about using FastSpring & LimeLM together that covers the basics.
So, depending on how you setup things in LimeLM, you'll have to modify the script a bit for the different licensing plans you're selling.
Would 1 product handle all scenarios?
Yes, you can create a single product in LimeLM.
For "single user" use you'll want to use TurboActivate.For "network user" use you'll want to use TurboFloat.For subscription use (either network or single user use), then you'll want to use custom license fields.
Tell me if that helps.