You could try removing the fuse(s) that cover(s) the lights you mentioned and then see if the starting can be reproduced.

However, the starting issue is likely to be caused by something else. For example, part of the engine software can become corrupted and require reinstalling/upgrading.
Sometimes this happens as a result of a faulty electronic circuit component. A circuit tracer is required to located the offending part.

i fitted led side light bulbs to my 09 reg focus no probs at all.