Yes, you could update the parameters to include this field, assign the field value to a variable, and then pass this variable to the e-mail section. I have not tested this, but something like below:
emailList = []
params = {'f': 'pjson', 'where': "1=1", 'outfields' : '{0}, {1}, {2}'.format(uniqueID, dateField, emailField), 'returnGeometry' : 'false', 'token' : token}
req = urllib2.Request(URL, urllib.urlencode(params))
response = urllib2.urlopen(req)
data = json.load(response)
for feat in data['features']:
createDate = feat['attributes'][dateField]
createDate = int(str(createDate)[0:-3])
t = datetime.datetime.now() - timedelta(hours=hoursValue)
t = time.mktime(t.timetuple())
if createDate > t:
oidList.append(feat['attributes'][uniqueID])
emailList.append(feat['attributes'][emailField]
print(oidList)
FROM = fromEmail
TO = [emailList]
SUBJECT = 'New Features Added'
TEXT = "Features with {0}s {1} were added.".format(uniqueID, oidList)