There's no way the Sens make this swap.
Lazar is going to be a dirt cheap third liner for the next three years (see Pageau extension) who in a third line role is likely to be more effective than Yakupov. Production wise, Lazar wasn't that far off Yakupov last year. Although Lazar hasn't been great, he has all the tools to become a solid physical third liner who can chip in 30+ points. The Sens have also yet to see what Lazar can accomplish under this new coaching staff, so trading him now for a project like Yakupov would be short sighted unless they were getting back a known element like they did in the Brassard deal. With Yakupov further along in his career and having spent significantly longer at the pro level, the odds of Yakupov putting it together at this point and become a good all around top 6 player are probably similar to the odds of Lazar breaking out and becoming a top 6 player.
If Ottawa were to make a swap with Edmonton, I think they'd try to offer Puempel for Yakupov. I don't think Puempel is exactly done in Ottawa, but especially with there being a perfect opportunity at 2LW for him due to Mac's injury, this year might be the end of the road for him if he doesn't grab the brass ring. If the Sens aren't sold on Puempel after this training camp and think Yakupov has greater potential or is a better fit, I could see that being a trade they try to make since they'd already have to cut a player they otherwise wouldn't have cut if they claimed Yakupov.
With that said, I'd be surprised if Ottawa claimed Yak. I'm not saying I'd be disappointed, but for a budget team like Ottawa committing 2.5M to Yakupov instead of 600k-900k on a replacement player would be a big statement.