The bow and stern padeyes are well anchored. They screw into embedded brass inserts cast into the hull. I would suggest you tie a loop of small diameter line through the padeyes for a transport attachments. I use "550" parachute cord (550 lb. test) -- small diameter (1/8" +/-), inexpensive and strong. I also use it as a permanent bow line and for various other small tasks. You can get it on e-bay or your local military surplus store. The lift handles are best used for lifting only IMO.
Keep in mind you can install custom padeyes (or other hardware) for any purpose. Using Stainless steel, you would through-bolt and use flat washers (to distribute the load) and lock nuts. Just be sure you can reach the desired location from the inside!
Fitting the boats side by side is a function of rack width, not car width. Of course, it might look funny having 76" bars sticking out and they could possibly pose a safety hazard. But then, you can take a wide bar and cut it down for a custom fit. For instance, two 30" wide Sports = about 60" -- that shouldn't be too much of an overhang. Bars are available in assorted widths, are easily trimmed, and with most mounting systems, are fully interchangeable. I'm sure you'll work it out.