Unfortunately, you don't have option to change this 2 settings in PnP powershell, In fact this are not available in SharePoint powershell also. You have to rely on list.asmx webservice to do this.... Below is example using CSOM, you either have to convert to powershell or us in C#.
Ref link - https://social.msdn.microsoft.com/Forums/exchange/en-US/d664cb09-fbd7-495c-880f-61e3268bfd94/creating-sharepoint-online-survey-list-programmatically-and-set-properties-allowmultipleresponses?forum=sharepointdevelopment
XmlDocument xmlDoc = new System.Xml.XmlDocument();
XmlNode ndProperties = xmlDoc.CreateNode(XmlNodeType.Element, "List", "");
XmlAttribute ndTitleAttrib = (XmlAttribute)xmlDoc.CreateNode(XmlNodeType.Attribute, "Title", "");
XmlAttribute ndDescriptionAttrib = (XmlAttribute)xmlDoc.CreateNode(XmlNodeType.Attribute, "Description", "");
XmlAttribute ndDirectionAttrib = (XmlAttribute)xmlDoc.CreateNode(XmlNodeType.Attribute, "Direction", "");
XmlAttribute ndMultiresponse = (XmlAttribute)xmlDoc.CreateNode(XmlNodeType.Attribute, "AllowMultiResponses", "");
XmlAttribute ndShowUser = (XmlAttribute)xmlDoc.CreateNode(XmlNodeType.Attribute, "ShowUser", "");
ndTitleAttrib.Value = "First Survey";
ndDescriptionAttrib.Value = "Custom Survey";
ndDirectionAttrib.Value = "LTR";
ndMultiresponse.Value = "TRUE";
ndShowUser.Value = "TRUE";
ndProperties.Attributes.Append(ndTitleAttrib);
ndProperties.Attributes.Append(ndDescriptionAttrib);
ndProperties.Attributes.Append(ndDirectionAttrib);
ndProperties.Attributes.Append(ndMultiresponse);
ndProperties.Attributes.Append(ndShowUser);
string webServiceUrl = ctx.Web.Url + "/_vti_bin/Lists.asmx";
StringBuilder sbEnvelope = new StringBuilder();
sbEnvelope.Append("");
sbEnvelope.Append("");
sbEnvelope.Append(String.Format(
"" +
"" +
"{0}" +
"{1}" +
"{2}" +
"{3}" +
"{4}" +
"{5}" +
"" +
""
, id, ndProperties.OuterXml, String.Empty, String.Empty, String.Empty, version));
sbEnvelope.Append("");
HttpWebRequest req = (HttpWebRequest)WebRequest.Create(webServiceUrl);
req.Method = "POST";
req.ContentType = "text/xml; charset=\"utf-8\"";
req.Accept = "text/xml";
req.Headers.Add("SOAPAction", "\"http://schemas.microsoft.com/sharepoint/soap/UpdateList\"");
req.UserAgent = "FrontPage";
req.UseDefaultCredentials = false;
Uri targetSite = new Uri(ctx.Web.Url);
SharePointOnlineCredentials spCredentials = (SharePointOnlineCredentials)ctx.Credentials;
string authCookieValue = spCredentials.GetAuthenticationCookie(targetSite);
req.CookieContainer = new CookieContainer();
req.CookieContainer.Add(
new Cookie("FedAuth",
authCookieValue.TrimStart("SPOIDCRL=".ToCharArray()),
String.Empty,
targetSite.Authority));
using (IO.Stream stream = req.GetRequestStream())
{
using (IO.StreamWriter writer = new IO.StreamWriter(stream))
{
writer.Write(sbEnvelope.ToString());
}
}
WebResponse response = req.GetResponse();
using (IO.Stream responseStream = response.GetResponseStream())
{
XmlDocument xDoc = new XmlDocument ();
xDoc.Load(responseStream);
if (xDoc.DocumentElement != null && xDoc.DocumentElement.InnerText.Length > 0)
{
Debug.WriteLine(String.Concat(DateTime.Now.ToShortTimeString(), " Response of the Survey List Update: ", xDoc.DocumentElement.InnerText));
}
}