Three Player Snipers
This is a variant of my two-player snipers because my brother wanted to join as we cleared the Dream-chaser Cycle
With three players, you can do a fairly solid job at dividing up the roles.
Tactics I pushed Argalad into his own lore side and added a (MotK) Bofur so that we can get a solid quester in tactics and then once blue is up and running on the questing front, he can provide some search for attachments. Ideally, we are abusing Ring of Thrór to get more attachments into play. This player will struggle with the sailing tests as there aren't a whole lot of allies in the deck. However, the allies that are in the deck are cheap. Don't be shy to share the love; the only thing that's needed on this side is Sting and Ring of Thrór. Blue should also play Hobbit Pony to get the most out of Bilbo Baggins' ability.
Lore I included Mirlonde, who raises your threat slightly, if you get sick of seeing Stinker. Otherwise, this deck does pretty well staying under the threat level of most of the enemies that will pop, allowing you to trigger Haldir of Lórien. Now, Argalad is a good target for Light of Valinor and Mirkwood Long-knife, and that should be enough for him. Haldir will need a little more juice to make his ability a full-blown snipe. As for Smeagol, well, just use his money first and use his ability very conservatively.
Ideally, we will see some serious threat reduction on this side. This is where the fellowship feels less like snipers and more like a "pouncing" deck -- Merry reduces based on threat of the revealed enemy, Engage it, defended with Fastred (who is a great target for Raiment of War) and then kick it back to staging area to reduce your threat... how much that round? A lot. Hopefully you can get to Song of Eärendil to keep everyone's threat down, but with an additional player involved, it becomes a little harder to manage everyone's threat. Hopefully, Tactics deck can begin to take care of itself, so mostly help with Lore in that regard. Otherwise, Tactics needs to toss stuff over to Blue quickly. Eomer and Fastred become quite a team, but only with weapons or mounts.
Overall: Pray for enemies. Locations are deadly with this fellowship, and this might be a good fellowship for the newly spoiled "Bilbo's Plan". Once an enemy flips, everyone pounces: --Merry threat reduction --Bilbo & The Hobbit Pony --Thalin one damage --Eomer Grappling Hook/Late Adventurer --Argalad to finish him off. --Haldir readies with Wingfoot
It's a sight to behold.