Honestly, seeing teams really depends on how skilled at the game they are and how good at double teaming they are. I am just gonna say each team is a group of average people who have routes on some maps and sometimes they aren't the best and have some PvP skill but it could really use some work, maybe around 50 wins each. Also, taking down teams could be harder/easier based on the map, terrain of the map, what your gear is or what theirs is, how many arrows you have, etc.
Team of 2: Basic bow and FnS usage, then some sord hits to finish them off.
Team of 3: FnS really comes in handy, normally I wait for them to be split up, or at least have 1 of them not be with them so it is basically killing a team of 2 and killing the third guy later. More bow as well, and then more sword. Golden apples could be useful as well.
Team of 4: This can be tough, but with enough skill, FnS, and bowshots, I might just be able to pull it off. A lot of my strategy at that point is just hit-and-run strategy with some turn around bowshots and turn around FnS placements. After feel like all of them are low enough, I go in for the kill with the sword.
Team of 5 or greater: These can be very difficult to take out, yet very rare to find. You really need to have them be split up for it to work, unless you are just that much off a boss. Again, more of what I do versus a team of 4 but added in would be me going in with a sword until I'm low and then running and doing the turn around bowshots/FnS placements until I have regenerated a majority of my hearts, and then I repeat that process, obviously finding times to eat if I can. Most of the time a team of 5 will be more experienced players because if a team of 5 noobs played as a random team in the lobby chances are a majority of them won't survive until when they can meet up, as they are noobs, making it usually much tougher.