SharePoint 2013 Extranet setup recommendation

for an Extra-net SharePoint 2013 application having 3 WFE1 APP server1 index server1 DB serverwhat will be correct recommendation. Hardware configuration of servers are known to us but what will be set up of 

1. WFE servers? - implemented in DMZ?How will be firewall setup both hardware & software firewall? 

2. Forefront servers recommendation?

3. Reverse proxy recommendation?

4. Aany other major factors to keep in mind?

Project is for a medium size client. Pl guide