Whereas I really can't be sure what my dogs would do, here is what I suspect they'd do:
If I weren't home and all four dogs were loose in the house (would never happen, but just for theory sake); all four dogs would be very vocal. Once the door was opened, Lonestar would make a break for freedom. I'd find him in the next county. Maggie could possibly take down the intruder, if he didn't notice her while coming in and tripped over her. Tug would bring him a toy and then bite him when he reached to take it (I know this for a fact). Hondo would stay engaged. I don't know if he'd bite or not, but he wouldn't back off and remain vocal.
If I were home, all four dogs would be fighting amongst each other to check out the bloody remains on my floor. Body piercing by Ruger.
Hondo Von Dopplet L Bauernhof "Hondo"- GSD
Lilie's Tug McGraw "Tug" - Golden Retriever
Maggie - Mini Dachshund (Rescue)
Lonestar Pivo - Texas Blue Lacy
Ashe - Barn Cat
Katie / APHA