With limiting the number of posts which Newbie(i think Jr.members need to be in this group) can post daily, it is necessary to get approval for each post before publishing. So it can't be published any post without approving from forum moderators. Yes there can be a problem it is a lot of job for forum admins and mods, but this can be facilitated if more members are included in the moderation.
1) This is not a good suggestion. A newbie might be joining here to ask some doubt and delay in approval will make him go to alternative forums.
2) Problem 1 can be solved with the suggestion you gave, having a lot of members in moderation team. Are we prepared for that ? The staff might be having an idea based on how many members participate in such activities already like reporting posts here.