The connections are different. Pin locks have pins on the post. So you can not hook up a gas line to the liquid post and vice versa.
I have not owned any ball lock kegs or seen any but my understanding is you can accidently connect the lines wrong.
I chose pin lock due to cost and availability.
It's been mentioned in other threads. But you can use ice to chill it the last bit. Either bagged ice or making your own with plastic tupperware. Someone mentioned the thin plastic stuff from like dollar store. Use the quart size ones. Fill up 4 and freeze the night before then pop in 4 frozen...
North Houston here. Brewed today and could only get wort down to 87. Stuck it in my fermentation chamber for 4 hrs to bring temp down to 70 to pitch yeast. Think next time I'm going to dump a 10lb bag of ice in to bring it down once IC has run its course. Just need to compensate for the water...