If you inspected them well and know for sure it was just those 6, you should be good, but will still be exposed to where it could hit you again in no time. Keep a close eye on them at all times. Consider filling a spray bottle with hydrogen peroxide and lightly spray the areas where it was infected. You do not want to soak with the peroxide, but it will help disinfect any disease/bacteria that could be remaining on the stalk/leaves, if any at all. That would be a good, cheap safety precaution.
I'm a greenhouse grower, and understand your concerns of bud rot, as that's one of the big reasons I chose to do a GH. You could immitate the GH effect with cheap resources if you want to take the extra time, effort, & maybe spend some $ if you feel the end results will result in yielding enough to cover your costs/extra investment AND SOME. If not, don't bother.
What you could do tho, is set out some cheap wood stakes/posts, garden stakes, ... After you have a stable perimeter around your plants, throw some clear plastic, tarp (i like the 4mm or 6mm clear plastic that comes in a roll/box @ home dept) and create a cover, mini greenhouse.
You can even take outdoor extension cords and throw fans, heaters, dehumidifers, whatever you need and as long as you keep it well covered, you can create your own lil controlled enviornment in there if you have all that other stuff.
