I agree solicitors need to be paid but just a few hours of their work will add valuable information and allow an informed decision as to whether it's financially sensible.
You really do need a solicitor; this is a right tangle and I can't stress this enough. It would seem you have not just regular will/executor/tax stuff but possible other areas even stretching as far as criminality if there was undue influence used. Just spending a single hour talking this...