Someone let me in on a trick to start workflows without the "Start Screen" by making setting Form Type "Custom" and deleting the Start Page line. It works fine when you click on the workflow by clicking on "Site Workflows" from "Site Contents" and then clicking on the workflow you want to start.
When you use the "Custom" form, there is no longer a URL to go to. I would like to add this action of not having to click "Start Workflow" to a button.
The other thing I'm trying to configure for my users is the Workflow Landing Place---the place the workflow dumps you out when it has had its way with you. The place seems to be back on the "Start a New Workflow" page and this is confusing for my users because there is no recognizable navigation on the page. I know how to route around but they just get lost.
For your second part, I presume you mean the redirect once you have clicked the button and the workflow has started? If so, if you use the web service approach above, you can do what you like with your user after they click the button.
var obj = NWF$(".cssSubmitButton");
with a css class on the start button on your custom form of cssSubmitButton will mean the form is submitted with you having to click start.