Part 121 High Mins Question

I need some clarification regarding dispatching a flight with a high mins captain. I know we add 100’ and 1/2sm to landing but ceiling isn’t a landing requirement so that part confuses me.

1. For the destination, visibility is the only controlling landing minimum to dispatch correct? So I just add 1/2sm to the visibility?

2. For the alternate, you don’t make adjustments with the caveat they can’t be below 300-1sm.

3. For takeoff, it doesn’t apply.

4. For takeoff alternate landing minimums, you add 1/2sm to visibility.

It is my understanding the 100’ ceiling part really only applies to the pilot for MDA/DA as ceiling isn’t a landing minimum. 
 
Does that all sound correct?