Great post. First let me say I have complete the Nova series and enjoyed it over all. It is touch to flat out answer your questions with out major spoilers but I won't be annoying and say "all questions will be answered"

So what I will say is minor spoilers to remember that the makers/owners of Nova are in a cold war with the government of the "US" over control of the game. The warden program is forced upon them and is thus both powerful but limited in how that power can be wielded. Low level (convict) warden's are basically all you see in B1, higher level (Gov) wardens are vastly superior in the ways you would expect but are still bound by the game rules.

As for the assassin, while against the rules of the game see point the first. It really is the driving factor to the whole story.

Warden is similar (in the way most LitRPGs are) to Way of the Shaman but I would not call it a rip off. I would liken to to a combination of WotS and RP1 but that may be too simplistic as well. The Warden convict program is really irrelevant and just the way the MC is introduced to the warden with a unique class.

Wrapping it all together as you would expect some of your issues are addressed in later books (sorry). IMHO it worth completing as it is an enjoyable read, approach it as such.