Well, for enemies so early in the game you don't really need much team-setup based strategy, but

Okay, so, Sam as Tank means Water Tank
Here's our own starter (so stats at the same level) who is also set up as a water tank.
We personally aren't much of an HP person, but in the Lost Grove his base HP couldn't stand up to some of the Elites+Bosses while we were training up his attack ranks, so he gets one (our other water tank is a max stat and is 3str/2agi, since he has a far higher base HP). The Strength on a water pet directly affects their move output (the Physical Damage stat is Str/2 (rounded up)+Relic Bonus; Munir as example, his Str 984/2 = 492, + relic bonus 600 = phys damage 1,092)
(obviously, for the three magical elements the relevant ones in the calculation are magical damage and Int rather than phys damage and str)

so, high str on a sub-lv65 water pet means bolt does more damage and can in turn absorb more daamge, and Ice Barrier can absorb more damage and restore more HP in turn.
Higher Agility means the pet has better chance at evading incoming attacks and has higher defences in general, and more speed*
(note: Agi and Dex control a pet's speed equally, a pet with 1 dex gets the same speed boost as a pet with 1 agi, so you don't need to put agi on non-tanks for them to be faster)

A water tank at lv60+ is best equipped with Tidal Lord equips (with Exotic ones being the easiest and cheapest to find on the broker since they're the regular equip drop from enemies in the Grove- Vinethorn tier are more expensive since they only drop from Bosses in the Grove, and Stoneweave are Extremely Expensive since you need to get a legendary rarity drop from one of the three cave bosses to even be able to start the process of making one)
Warden equips from the LG can also be put on a water tank, though they tend to go to earth tanks (but really it just depends on if you want to lean towards Str a bit more than agi (tidal lord) or agi a bit more than str (warden)

She should be in slot 1 of the party, since that's where

For the other two it doesn't matter as much who goes in which slot (I personally keep my healer in 2 and attacker in 3, but that's just a matter of preference)


Blueberry! As the Light healer!
Light healers are typically statted (at lv70) 3int/2dex profs-wise, and equipped in turn with Evoker (non-lg) or Pyromancer (LG) (Lightbringer equipment is for light tanks, not healers, and it trips a lot of people up)
You want to have that int so the pet can give the team the best healing it can!
(currently his magical damage stat is 280, so currently his beam is outputting 280 and healing each pet on the the team 140 per hit.
If he had 4 Exotic Pyro equips and 3int profs, it'd be... 717, if I got all my math right, which would be 717 damage from each beam and 359 healing
Light healers get dex since dex controls accuracy and critical hits
(here's my main team's light healer as a reference)


An attacker- either Air or Fire usually (you can keep Tommy on team if you want, it'd be as simple as swapping his element.)
Profs at lv70 on one are 3offense/2dex
lv60+ equips are storm caller for air (myrmidon failing that) or pyromancer for fire (evoker failing that)
example pets: our main team's air attacker, and secondary team's fire attacker)

Obviously this is just generalist stuff- you could, for instance, do a shadow attacker (more survivalist than fire and air, but slower on the damage), or have some hp prof on all pets (again, less damage output overall, but some people like the safety of it I guess?) Tank prof setups are generally the most varied between the user's style and preference and the pet in question