Certificate errors if i'm not wrong can be handled (ignored) inside app if needed.
About proxy / 1255 version has already fixed bug in newer version with race conditions on initialization. So you need use more recent version, which compatible with current cefglue version.
PS: I'm will try update cefglue on this weekend to newer cef branch, - sorry for delay... Probably it will solve your's initalization problems out-of-box.