Your signings are all reasonable enough! However giving up way too much for Muzzin! Retaining money. . . .a solid top 6 forward, and 2 solid prospects, one with 20 goals? All of that for a guy whose big time upside is a 3/4 Dman? I would question, giving up Brown and Carrick alone for Muzzin?

The Vegas deal is interesting and probably fair value. I agree that is an overpayment for Muzzin.

Also confused by the type of LA deal. Leafs obtain a LHD (not a position of need) for a RHD (a position of weakness). Yes Muzzin is better but still, why? And then to trade JVR a LWer a position of weakness for the Leafs too.
Rychel, Leipsic two minor leaguers who may/may not of be NHLer and not seeing the ice Leivo at LW next year, and a 20 goal scorer.

Muzzin is a legit top pairing defenseman, and those do not come cheap. Honestly, LA might ask for even more. If Toronto can manage to add one at that price (i.e. without giving up any of the big 3) they should be all over it. They have a ton of winger depth to play with.

The leafs need better defenseman period. Would it be nice if they could have 3 lefties and 3 righties? Sure. Should that be a reason that they don't add a top pairing defenseman? Absolutely not. Muzzin is lightyears ahead of Carrick so the fact that you're giving up a RHD for a LHD is so insignificant. Rielly can play on the right side if you need him to.

Also, not sure why you're worried about whether Leipsic and Rychel are NHLer's or not if they're only your #13 and #14 forwards - you could do much worse than them. I didn't understand the rest, but Leivo absolutely deserves an extended look at the NHL level: he has done nothing but produce every time he's been given a small opportunity.