All of that^.
I would for sure make sure you both have a rock solid "whoa" prior to doing any kind of bridless - I decided one day to try riding my mare in my 'riding area' [aka the flattest part of her pasture] with a neck rope instead of a bridle.
All was going great - she was stopping perfectly, turning on a dime, it was just like she was wearing 'more' than nothing...until I accidentally dropped one side of the neck rope [I hadn't tied the ends together]. Turned out that she indeed has turning down like a pro, and will even slow from a trot to walk bridle/neckrope-less...but she really doesn't understand walk to whoa without some kind of non-seat control [always been a sticking point, she has more go than whoa! haha].
Luckily she's a sweetie pie and just walked around slowly - until I managed to acrobat myself around her neck, get that neck rope re-situated, and get her stopped.
But if she were more inclined towards mischief...yeah, I'd probably be dead.
And she's 29 in February. Of course, she's only been really 'broke' for 4-ish years - with limited 'arena' work..but still. If a nearly 29 year old horse can out-sass her rider...
So make sure that whoa works!