Yes. Funkins are resistant to all kinds of weather including rain, sleet, snow, sun, cold. If wind is a concern, make sure your Funkins are weighted down, they are much lighter than pumpkins.
No. Never use real flames inside Funkins, this could result in fire. There are plenty of options available for lighting pumpkins and Funkins that are safer than real flames such as the Funkins Pumpkin Light and the Funkins Battery Operated Tealight.
Funkins are made of patented low–density polyurethane foam and are painted with polyurethane paint. The walls of Funkins are about one half of one inch thick (varies with size of Funkin). And Funkins are already hollow. This makes them just as easy to carve as real pumpkins (without the gutting and the mess) and very realistic looking.