Input needed on single player adventure

[DementedFellow]

So I have a player who wants to give D&D a shot. He will be playing a Muckdweller Rogue. His AC is pretty boss, and he can combine the racial squirt ability with a sneak attack. I would dare say that he might even be overpowered for his level as much as one could be all things considered.

He also wants to have interaction with human-like cultures. Which means to me at the end of this first arc, he will be rewarded with a Hat of Disguise.

So here is what I have in terms of a storyline.

The setting will be a swamp adventure. Our story begins as the player is looking for a place that would make for a larger home in the swamp. His expedition leads him to an abandoned cemetery near the edge of the swamp. There is a river nearby and plenty of food to be found. Place seems quiet enough right?

Muckdwellers are really good at making burrows and within a few hours he digs a nice place in the soft soil. Cut to the wee hours of the morning. He is awakened by some noises. He goes out to investigate.

2 dwarves and their 2 dogs arrive to the gates of the cemetery with a cart. It's pretty obvious that they are graverobbers and the guards are there to walk the perimeter and start barking should onlookers be found. The dogs are also trained to attack on sight.

This is where things get interesting.

I will give the player the option to take out the dogs and the graverobbers.

Should he decide not to intervene, a dog will discover the burrow will start digging and discover the muckdweller.

It gets better. After a certain amount of time, the graverobbers will unknowingly trip a trap and they will have to fight off creatures of their own. Around 6 Crawling Claws will be alerted that intruders are around and will engage and fight them.

Hilarity ensues.

Turns out deep in one of the crypts we have a fledgling new necromancer who put the Crawling Claws in place to guard his evil workings.

After a certain amount of time, his familiar (beholderkin, no less) will go out and investigate and clean up the excess. The player will be given an opportunity to kill the beholderkin familiar. Naturally, this will anger the necromancer in the tomb below.

I plan for the necromancer to be level 3. I know that the player can do well against the fight above the crypt, and he should level from just that encounter alone.

I have questions though.

1) Can loss of experience from a familiar's death result in a loss of level?
2) I plan on giving a couple magic items to the player once the necromancer is dead, namely the Hat of Disguise, but what items should be found in the graverobber's cart? Magic and mundane item suggestions are appreciated.
3) Can a level 2 rogue take out a level 3 wizard who just lost his familiar?
4) What are your overall thoughts on this scenario?

Thanks in advance

[rockdeworld]

1) Can loss of experience from a familiar's death result in a loss of level?
2) I plan on giving a couple magic items to the player once the necromancer is dead, namely the Hat of Disguise, but what items should be found in the graverobber's cart? Magic and mundane item suggestions are appreciated.
3) Can a level 2 rogue take out a level 3 wizard who just lost his familiar?
4) What are your overall thoughts on this scenario?
I want to say that for anything like this, I recommend reading this article (http://www.bluemoonaurora.com/duetroleplaying.htm).

Now to answer your questions:
1. Yes.

If the familiar dies or is dismissed by the sorcerer, the sorcerer must attempt a DC 15 Fortitude saving throw. Failure means he loses 200 experience points per sorcerer level
2. Everburning torch, shovel, Ring of Protection +1, Cloak of Resistance +1, and Gloves of Dexterity +1 are all useful.
3. Yes. The degree of effort ranges from "trivial" to "impossible" depending on the circumstances, which are up to you.
4. It sounds overpowered for the character. Being alone makes every encounter much more difficult, due to the loss on action economy. You'll get a better idea after reading the link I included.