I have a feeling the "weep hole" was someones attempt to keep the crack on the bottom from spreading, but to no avail. That is common for them to crack at the vent. Main reason to use no more than 30 briquettes at a time.
Hate to be the bearer of bad news, but any paint that I have tried to cover JB Weld has not adhered and flakes off rather quickly. I even tried roughing it up and it won't take.
I have repainted this twice after the initial base coat of BBQ Black paint and it still flakes off in the areas repaired with epoxy.
Toss the charcoal grate and get either a Lodge cast iron trivet or a BGE iron grate.
Good luck! You are off to a great start, keep us posted on the progress!