I disagree harshly on the line combinations, but personal opinion aside - Is it worth selling off Pageau and DeMelo? I keep seeing people trade them off and never really entertaining the idea of keeping them around. In my eyes, I see DeMelo as Methot and Chabot as Karlsson in this rebuild, a solid duo that has no real reason to be split unless things start going south for them. In Pageau's case, I see us re-signing him because he's the familiar face along with Anderson, Borowiecki and Ryan, the only ones to have spent more than 3 seasons and a 'selling point' or face of the team for the fans (though that's mainly Chabot now). I've always liked the idea of him playing 1st RW with Tkachuk and White, being the veteran presence on that line and a solid two-way contributor (not the mention playoff warrior when we actually make it)

If it turns out there is a log jam at centre and we start selling off some pieces to make room for more young guys, then I see Tierney being a better (higher value) trading asset, as he's coming off a pretty strong season on a very bad team. I might also look to flip Anisimov instead (and maybe eat a bit of salary) due to the extra year on his contract. On defence, I agree Hainsey is most definitely being moved - as while I don't see Lajoie being a permanent blueliner, I can very easily see Brannstrom getting the call fairly early and potentially multiple times across the season if he somehow doesn't stick around for the whole year

The line combinations are whatever, you can stick them in a blender and they'll be just as accurate as what I came up with, I'm thinking anyone who is a pending UFA trade, the reason being that odds are they aren't going to want to resign with the team that is probably gonna be bottom by a large margin. JGP could get you a decent return, as could Boedkker at the deadline, and as a rebuilding team to me it just seemed smarter to sell of any pending UFA's so the team regathers maximum value, leaving as few UFA's as possible to walk away from the team

I agree that UFA's are selling points but you still need a few veterans to help keep the kids stabilized. Pageau and Demelo still have roles to play and can fit up and down the lineup if need be. While they might garner a bigger interest around the league, there is incentive for them to stick around and if the price isn't right, I'd re-sign them to a 3-4 year contract. I think Demelo also has way more value then a 4th round pick.

Dylan DeMelo is not getting traded and certainly not for a 4th round pick. He's a first pairing RD for this team and their best defensive defensemen who can also move the puck. Wouldn't be out of this world to ask for a late first for him. But he isn't getting traded. At this point he is way more valuable to this team than yet another pick.

Also Morgan Klimchuk is going to have a hard time making Belleville's roster at all, let alone Ottawa's roster and certainly the top 6 of Ottawa's roster.

And Colin White is the first line centre not the second line right wing.

I don't see OTT getting a 5th for Ennis, Borowiecki or Anderson (unless a playoff bound team has lost their starter or backup to injury and Andy is having a good year).

I'd obviously like to extend Pageau and Demelo but since their UFA it will be there choice, not ours. That being said DeMelo should get a MUCH better return, and I think Pageau is being undervalued a little too. A playoff team that gains a pivot capable of playing the middle 6, who is an elite PK guy, who can shadow/shutdown one of the oppositions best players night after night... I'd be looking for at least two 2nds. Even more if you can get an agreement in place for Pageau to sign with them.

I've really liked DeMelo since he came over. It also seems to be a trend in Ottawa that these late draft picks find a home/blossom here (before we trade them away). I agree that he has much more to give to this team than a 4th rounder (or even a second), you might be able to pry him away from me for a first though... and OP did say that the lines weren't accurate and could be thrown in a blender, so... *shrug* I'd go for something like this, assuming that C. Brown, Hainsey, Anderson (unlikely), Boedker, Ennis are traded:
Tkachuk - White - Pageau
Duclair - Tierney - Batherson
Anisimov - L. Brown - Verroneau
Balcers - Chlapik - Ryan

Chabot - DeMelo
Wolanin - Zaitsev
Boro/Brannstrom - Jaros

Nilsson
Hogberg