As a Thug/Traps it best to fully slot pets soon as possible as you lvl up I normally have Assault by lvl 10. and work so I can get stamina at lvl 20 then use slots when 21.
As for powers Web Grenade, Caltrops, Acid Mortar, Force Field Generator, poison trap, Seeker Drones, and land mines are good to have. Triangle Heal and Time Bomb I found not so useful.
Fully slotted Aid Others is good for taking care of your pet and take Aid Self doesn't need be slotted. For pet upgrades just leave them unslotted and use a end reducer on it. Pets I generally use 3 acc 3 Damage while lvling up
When it some to Enchamants I personally use IO's the ones you you make soon I hit lvl 12. I found that stable performance is alot better then a tempy boost in power possible failer of store bought enchantments bring. I normally use what ever find I to make them my IO's. You can do good with lvl 25 IO's when lvling.
I've found Triage Beacon to be fairly useful for positioning correctly, and the extra regen does help.
But, primarily, you want to focus on recharge, recharge, recharge. Its very important for a traps MM to have LOTS of it. The more traps down the better.
As a Mercs/ MM it's generally a good idea to pick up Achilles' Heel: Chance for -Res Debuff and slap it in Soldiers and Spec Ops, since your /traps you can slap it in Acid Mortar, too.
I set up a Merc/Trap MM and i like the build but i havent gotten too deep into him yet so im trying to think about how to slot him and i dont want to do somthing too stupid on him so im trying to get some ideas on how to go about laying out his build on mids befor i do anything im going to have Leadership and fitness fitness at least till it becomes inherant and posible concealment im kinda debating on what travle i should go with. I weclome any advice on how to slot and what to grab and what not to grab.