I don't think Edmonton would bite on Pacioretty as the main piece unless Lucic was also involved, which would free up the salary to extend Patches.
Pacioretty, Shaw, and Juulsen for Draisaitl and Lucic would be about fair value (no overpayment), but you likely won't convince Edmonton fans here of that, based on what I've seen.
Pacioretty is typically undervalued for a number of reasons, but the fact is, he has 40 goal potential for a number of years next to an elite center like McDavid. He also plays a two way game and kills penalties, where offensive wingers are typically less reliable in those areas.
Shaw is treated like a bad contract, when he is in reality within about $500k of what he is worth. Take Eller for example, who just signed an extension. Eller is the better center, but Shaw is younger and more versatile. He also brings those extra elements that the Oilers lack.
Juulsen is a promising top 4 RHD, who will likely be ready before anyone Edmonton has in the system, should surpass Benning in short order, and hopefully be top 4 capable by the time Sekera or Russel's NTC's expire and they can be moved out.
Taking Lucic affects the value offered for Draisaitl. As much as I would prefer not to have Lucic on my team, he does have history with Julien, and perhaps he could offer hope to get better performance out of his former player.
Montreal may need to add a 2nd, with their own pick being roughly a late 1st this year, or perhaps a conditional 1st next season, based on Lucic improving his performance, but that comes down to negotiation between the two GMs. Neither is dealing from a position of strength. MB needs a 1C, while PC needs to put his team in a position to better compete. Something along these lines helps both teams, so anything extra comes down to who blinks first.
Weber would greatly improve Edmonton's outlook, but leaves Montreal with another large hole to fill. People have shown they can't be objective where he is involved. The focus always turns to age/contract, instead of what he brings to the table, and the contract concerns are negligible to begin with.
Gallagher is another popular option. Someone the Habs are not going to move unless they absolutely can not refuse.
Then there's Galchenyuk, who would be available in such a trade, and offers Edmonton somewhat of a do-over from drafting Yakupov. He may be more enticing than Paccioretty, but I'd avoid taking Lucic and add a non-top 10 pick instead, (Galchenyuk, Shaw, Juulsen, 1st or 2nd for Draisaitl and a "project" player). Montreal would be re-signing Paccioretty in that case, so no room to take on Lucic.
That's about the limits of what I would offer, and not without risk and hesitation.