Leave quotations in original (bad) English or edit?
Quotes should be included verbatim, so don't edit. Instead, insert or alter words using square brackets. E.g., "I'm wondering whether it is [okay] to leave the quotations as is..." Alternatively, replace direct quotes with a summary of what was said. Finally, use "[sic]" sparingly: Using sic "may be defensive, but its overuse is offensive" and "[in] truly minor matters it's usually better [to quietly] correct the original" (source: The Columbia Guide to Standard American English).