Endoscopy revealed diffuse moderate inflammation characterized by erosions & erythema in gastric body & antrum. Biopsies taken. Is cancer likely?

Wait for biopsy,,,,, At this point it's inconclusive to say and a clearer idea of this can be obtained once the biopsy results come back. Most stomach cancers are characterized by raised and thickened ulcer margins which you apparently don't have. Other cancers there are associated with blood disorders like lymphomas and have gastric thickening. Based on this cancer isn't likely but again, the bx gives more info..
Doubt it. Although cancer can only be ruled out by a biopsy, your description is more compatible with an ulcer and/or severe gastritis. I wonder why your gastroenterologist had not discussed the meaning of these findings with you.