Ciurciu is pronounced "Chur-chew" or "church you."
I think Lenon is far more likely to make the team than Ciurciu.
Lenon is a viable inside linebacker. As noted, he led his team in tackles. He hasn't missed games. He handles coverage and makes tackles. He plays special teams. Very versatile player.
Lenon fits in the four-ILB rotation with Mayo, Bruschi, and Guyton. While Mayo is clearly the best of the four, all four have experience and can play for extended parts of a game.
Ciurciu is solely a special teams player. As such, you need to look at a couple different parts of the roster. Primarily the ST roster, but secondarily the back-ups at other positions who can also function in the ST role, to balance depth on the roster.
At LB, the Patriots have:
ILB: Mayo-Bruschi-Lenon-Guyton
OLB: Thomas-Woods-Crable-Banta-Cain-Redd
At ST, in his size/position range, there is also:
Alexander-Appleby-Tank Williams-Alex Smith-David Thomas-BJGE
At LB, the first seven are pretty secure (Mayo-Bruschi-Lenon-Guyton-Thomas-Woods-Crable). One of TBC and Redd are highly likely to fill out the group. Both are possible. With nine LB, a 10th spot for another ST is pretty unlikely, given needs at other positions.
Comparing Ciurciu to the other ST specialists:
Alexander has some history on Pats special teams, and has played well in that role. Obviously many remember his role starting against Indy with an injured Pats team in the playoffs, unhappily.
Appleby offers some upside as an ILB, coming from Virginia's 3-4 system, and offers some size for the role. He is more likely to make the practice squad.
Tank Williams offers the hybrid SSILB role that Belichick likes (as demonstrated when Belichick brought in Lynch immediately after Williams was injured to try to fill that role).
Alex Smith, David Thomas, and BJGE are potentially competing for two roles as either a fourth tight end or fifth RB, and again offer a lot more to the offense.
With LB Lenon, Guyton, TBC, Woods, Redd, and Alexander all capable ST players, I think the odds for Ciurciu are long. The availability of other ST players at the big safety, TE, and RB position further decrease his chances.
Lenon is no lock. You can look at the Fernando Bryant situation last year as a decent analogy. But I think he's a lot more likely.