Following SAS program and its output are for the question #3:

SAS program:
proc phreg;
        model st*censor(0) = thick ulcer age type / covb rl;
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part of the output from above SAS program:

			The PHREG Procedure

         explanatory variables:

         THICK  ULCER  AGE  TYPE  

                             Model Fit Statistics
 
                                     Without           With
                    Criterion     Covariates     Covariates

                    -2 LOG L         903.925        821.457
                    AIC              903.925        829.457
                    SBC              903.925        838.564

                    Testing Global Null Hypothesis: BETA=0
 
            Test                 Chi-Square       DF     Pr > ChiSq

            Likelihood Ratio        82.4674        4         <.0001
            Score                  130.3918        4         <.0001
            Wald                    98.1662        4         <.0001

                    Analysis of Maximum Likelihood Estimates
 
                        Parameter      Standard
     Variable    DF      Estimate         Error    Chi-Square    Pr > ChiSq

     THICK       1       0.12888       0.04379        8.6619        0.0032
     ULCER       1       1.10409       0.27018       16.6993        <.0001
     AGE         1       0.02062       0.00802        6.6175        0.0101
     TYPE        1       0.83074       0.28560        8.4611        0.0036

                    Analysis of Maximum Likelihood Estimates
 
                                Hazard      95% Hazard Ratio
                  Variable       Ratio      Confidence Limits

                  THICK          1.138       1.044       1.240
                  ULCER          3.016       1.776       5.122
                  AGE            1.021       1.005       1.037
                  TYPE           2.295       1.311       4.017

                        Estimated Covariance Matrix
 
 Variable     THICK           ULCER              AGE            TYPE 

 THICK     0.0019177055     -.0027431829     0.0000171530     -.0049018142
 ULCER     -.0027431829     0.0729984038     -.0001830434     -.0222205262
 AGE       0.0000171530     -.0001830434     0.0000642797     -.0002209715
 TYPE      -.0049018142     -.0222205262     -.0002209715     0.0815646677