Yes pictures would help. With regard to the bumpers, on all the Europas from S1s through the last TCS the fiberglass follows the contour of the bumpers - front and rear. Many of the owners, who are no longer worried about shopping cart dings, remove the bumpers and fill in the small mounting holes. If you google images for Lotus 47, you will be able to see a little more clearly in pictures.
Like some of the early Corvettes, the bumpers are only mounted to the body (fiberglass), and are not likely to help with crash protection. Since it is almost an "optional" personal feature, there are always a few for sale. Sourcing a rear bumper should not be a problem.
Regarding the rotory engine, this would not stop me from looking at the car. A replacement 2.0L Ford Zetec, or 4AGE are popular transplants and with the right valve cover, twin carbs (or EFI) and a wild exhaust, they can be made to look semi period correct.
The best source for Europa knowledge is the Yahoo Lotus-Europa Group
https://groups.yahoo.com/group/lotuseuropa/
and Jerry's Lotus Europa Site
https://www.lotus-europa.com/index.html
Jerry manages a registry and has collected manuals, parts lists, cross references, and all the info you will need to keep any Europa in top condition.
Best of luck - Dean (HealeyBN7; ...and S2 Zetec in progress)