I am not absolutely certain what you want.
If you want one plot for the first and last subplots, rather than multiple lines in each one, sort them by first sorting ‘randgeneration’ and using that index for it and the others (the second and third subplots are histograms, so the order is irrelevant for them) —
mu = 1;
sigma = 5; % make the distribution as wide as we want.
N = 100;
randgeneration = randn(N,1)*sigma + mu;
[~,ix] = sort(randgeneration); % Create Sorting Index
pdfNormal = normpdf(randgeneration, mu, sigma);
figure;
subplot(2,2,1)
plot(randgeneration(ix), pdfNormal(ix));
xlabel('randomgeneration');
ylabel('pdfNormal');
subplot(2,2,2)
histogram(randgeneration);
subplot(2,2,3)
histfit(randgeneration);
subplot(2,2,4);
pd=makedist('Normal'); %create probability distribution object
cumulativedis=cdf(pd,randgeneration);
plot(randgeneration(ix),cumulativedis(ix),'r-.');
xlabel('randgeneration');
ylabel('CDF');
disp(mean(randgeneration));
disp(std(randgeneration))
.
