>> "Also, we have the Plus account and it says we only have 5 float licenses. How many float licenses are available at the other tiers."
I don't know where you're reading that. The 5 users refers to 5 "admins" for your LimeLM account: http://wyday.com/limelm/signup/
>> "Is there a way to manage leases on the server remotely [...]"
No, not yet. It's coming. For now the recommendation is to keep sane lease-lengths (30-minutes is a good length): http://wyday.com/limelm/help/turbofloat-server/#config-lease
This way the maximum time a "zombie" lease could exists is 29 minutes and 59 seconds (that's presuming the app or machine crashes *immediately* after requesting the lease -- and thus never has time to "Drop" the lease)
And of course a customer can always start the app on the same computer to "revive" the zombie-lease, and then properly close the app.