For everything besides the stash creation, I'd propose another solution by introducing fzf as a dependency. I recommend taking 5 minutes of your time and get introduced to it, as it is over-all great productivity booster.
Anyway, a related excerpt from their examples page offering stash searching. It's very easy to change the scriptlet to add additional functionality (like stash application or dropping):
fstash() {
local out q k sha
while out=$(
git stash list --pretty="%C(yellow)%h %>(14)%Cgreen%cr %C(blue)%gs" |
fzf --ansi --no-sort --query="$q" --print-query \
--expect=ctrl-d,ctrl-b); do
mapfile -t out <<< "$out"
q="${out[0]}"
k="${out[1]}"
sha="${out[-1]}"
sha="${sha%% *}"
[[ -z "$sha" ]] && continue
if [[ "$k" == 'ctrl-d' ]]; then
git diff $sha
elif [[ "$k" == 'ctrl-b' ]]; then
git stash branch "stash-$sha" $sha
break;
else
git stash show -p $sha
fi
done
}