It was actually easier than I thought. I mounted the ccd+img+sub in Alcohol 52%, opened UltraISO, Tools -> Make CD/DVD Image, uncheck "Skip Bad Sectors" (useful if it was a real CD), check "Enable ISO Volume Filter", select ISO as output format, select output filename and click on Make. Final ISO is 307200 bytes (300kb) smaller than the one created with ImgBurn, but otherwise identical in content if comparing both on HxD Hex Editor.
I just recreated all SVFs under slightly different names and reuploaded them all, along with scans of the cds (when available), and also a text file with information about the ISOs. Let me know if I missed something
E291F64566E128F71722B019821EC72428D49C03 5F4981DF 603.822.080 EN_WIN95A_951_SP1_COMPANION_OEM.ISO 17/01/1996 16:00:00, cdimage 2.11