Re : comment block in each wiki page
Each perms are set from admin -> groups -> click on the key of your group . In the new screen at the bottom, you have a filter (you can use all to see all the perms) and you will see the perm
(btw: perhaps you will enconter some bugs in 1.9 with tiki_read_comments and tiki_p_wiki_view_comments. A bug was found recently and I think not fixed yet)