Ok, unpacking the Ottawa trade here:

Hamonic and Watson have barely any value for the Sens so I would trade them for Johnsson.

That leaves Talbot for Blackwood, Walsh, Boqvist, Edwards, and a 3rd.

I'm not sure I'd trade Talbot while he's hot but value wise I would definitely do this from Ottawa's perspective.

Max Domi Is Washed

All quantity, not as much quality.

Devils shouldn't do any of these trades.

Boqvist, Walsh and Edwards combined are too valuable to deal for replacement level defender in Hamonic, a replacement level domestic abuser in Watson and Talbot to be the backup to Vanecek.
I suppose I could see one of the three dealt for Talbot if it becomes clear that Blackwood is not good enough to be a backup in New Jersey.

I see no point in the Devils trading for Domi as he'd likely be pushed out of the lineup as soon as Palat and Bastian returns from injury.
As such I'd rather hang on to Foote who possess a rather unique skillset within the Devils organization.

Dealing Tatar for Tarasenko is pretty much a self-defeating endeavour.
It's not obvious to me that at this point in time Tarasenko is the better player between the two.
He's got Tatar beat in point totals yes but Tatar's ridiculous ability in creating favorable conditions for his linemates weigh about as high as Tarasenko's production.
I certainly woudn't want the Devil to add Thompson, Mukhammadulin and a 2nd to the deal.

CHI declines.

These are bad for every team, including NJ

AJ salary is almost paid this year so I guess he could play in the bottom-6 and not cost much

Boqvist replaces Watson let's say (don't think Sens would want that though)

Hamonic with 50% retention is worth an asset, Talbot will be the most sought after goalie (but probably not as the Sens might stay in the playoffs hunt)

Edwards is meh, Walsh is more intriguing but not guaranteed Sens would be high enough on him

Not very enticing

I'd rather get less quantity, more quality

Remove Boqvist and Edwards, add a 2nd

If the Sens do eventually trade Talbot I would be happy with this package. Goalies almost never get a huge return on trades.