Are online-only first aid and CPR classes be acceptable for completing the requirement for ES qualifications?

No. CAPR 60-3 is clear on this point (ref page 18, paragraph 1-24f):

"When first aid or higher medical training is required for qualification in a particular specialty, the expectation is that the qualification course includes both knowledge and practical skills training; first aid courses taken online only are not acceptable; though members are not considered employees when supporting operations, courses are expected to meet the National Guidelines for First Aid in Occupational Settings available at or ASTM F 2171-02 (2009), Standard Guide for defining the Performance of First Aid Providers in Occupational Settings."