Wales probably goes through anyway, right?
How ties are broken within groups
If two or more teams in the same group are equal on points on completion of the final tournament group stage, the following criteria are applied, in the order given, to determine their rankings:
a. higher number of points obtained in the matches played among the teams in question
b. superior goal difference resulting from the matches played among the teams in question
c. higher number of goals scored in the matches played among the teams in question
d. if, after having applied criteria a) to c), teams still have an equal ranking, criteria a) to c) are reapplied exclusively to the matches between the remaining teams to determine their final rankings. If this procedure does not lead to a decision, criteria e) to i) apply in the order given to the two or more teams still equal
e. superior goal difference in all group matches
f. higher number of goals scored in all group matches
g. higher number of wins in all group matches
h. lower disciplinary points total based only on yellow and red cards received in all group matches (red card = 3 points, yellow card = 1 point, expulsion for two yellow cards in one match = 3 points)
i. position in the overall European Qualifiers rankings. UEFA