I'mmmmmm gonna say...hmmm...if we're talking let's just arbitrarily say 15th level...
Gonna need a rogue...I'm going to say an Arcane Trickster because a little extra distractionary/disguisey/disappeary magic certainly can't hurt...
...annnnnd...I'm gonna go with land druid. Large scale terrain and crowd control as necessary. Shapeshifting for scouting and/or packing a punch if needed.
Mostly, it's going to be an "infiltration." Fight/kill-to-keep quiet when necessary. Obviously the guards will need to be dealt with. But generally speaking, other than where the hostages actually are being held and the escape should be where all of your fighting needs to happen.
This is, of course, assuming you're talking about a thousand orcs in an established base/habitat (for 1,000 of them, I would assume so).
If it's 1,000 orc warriors in an army holding a bunch of people in a camp somewhere...probably keep the druid...but, well, actually, slipping in and out with minimum interactions is probably best. So, yeah. Same team.
If what you WANT (and your players understand) is going to be a toe-to-toe slaughter fest through ranks of fighters to get to the hostages and then, "YAY they're free [when all of the orcs are dead or fled]!" Probably need some serious heavy hitting...maybe a paladin...I don't think a barbarian could really stand their ground for too long...maybe a Champion Fighter...or, really, just use two druids or a druid and a cleric...druid and a wizard....just take out whole swathes of the enemy at a time, while maintaining protective spells or generating additional combatants (woodland beings comes to mind).
Yeah, bottom line, for 2 vs. 1,000 need to rely heavily on magic.