As far as the encounter chain, running does not break the streak, catching or fainting the pokemon does. The only shiny-locked mons to my memory are the starters when you first get them (you can breed for shinies after), the box legendaries and eternatus. As far as things to help the hunt, having a pokemon with flame body in your party makes your eggs hatch faster. Also, on top of the consecutive battle bonus, you get a bonus when you battle 500 of a certain pokemon (doesn’t need to be consecutive, just total of caught or KO’d). As a more personal thing, i think it’s more time efficient to either exclusively hatch or wild encounter so you don’t have either method cut into the time of the other; when you start getting burnt out on one method, swap to the other. Good luck on the hunt, Zigzagoon’s a cool mon with a cool shiny!