I'm no expert on commercial use, but I think your budget may be a little low for what you're hoping to do, depending on the type of drinks, throughput and level of quality you desire. I think it's likely you'll need to spend a lot more.
I would expect you'll be serving a high percentage of milk drinks, and if you expect to do that at high volume you'll need a rugged double-boiler machine. That's going to run at least $5,000-$10,000 for a single-group double boiler machine. And a single group may not give you the throughput you need. If you need a two-group machine, the price will go up substantially.
Will the kiosk allow you to connect the machine to plumbing? If not, you'll need a machine that can use a reservoir. Also, you'll need to bring a large water container to refill the reservoir and a large empty container to dump the drain box when it gets full. Note that the LM GS/3 machine is one of the few (if not the only machine) that's got a double boiler, is rugged enough for heavy commercial use and can run off a reservoir. You'll have to spend about $7,000 plus shipping for a new one, though you might be able to bargain a package deal with a grinder.
The cost of the grinder depends on the quality you desire. If you're serving mostly milk drinks, you can get a very rugged commercial grinder for $600 or so, plus shipping. But the grind quality and consistency likely won't satisfy straight espresso customers. For that, you'll need to spend at least $1,000. If you want the very best straight espresso quality, plan on spending $1,500-$2,500.