HI rye.

I have no concerns about an esc if it was watercooled and had a temperature overload feature.
A 7 ah gel cell battery is going to take a hammering and will not last a season.They are not designed for the discharge rate you are going to get.

By the way, those air cooled escs that quote the 100+ continuous amps you will need - the ones on ebay.They will not even run a single 700BB.

Tony Fitzpatrick