Thanny can do Garrison/Stronghold solo, so if you do a site solo, and then cap up, and warp in archon at 0 or at range w/e you want it's the same thing ISK wise, it just takes more time. Talking about 2 carriers at the same time, I haven't tried it but, you should use some RR between them for sure, not sure if you are planning just to triage one of them, and other one does the dps and keeps the aggro with ECM.
Anyways solo thanny + 2nd carrier at range spawning new sleepers is still more simple then that if you really can't use a solo dread + carrier at range.

I've done a Archon / Moros / Loki escalation by myself. The Archon boosts armor, the Loki boosts webs. It is scary. The Archon can permanently tank the 6/6 waves. With better skills and better modules I think you could perma tank 6/8, but you will want to try the test server to see what I mean by better skills / fit. Check out Miton's escalation guide for the Archon fit. You will want 2 named local reppers.

I'd go Archon then Thanny, and you will need to be on the ball switching the archon reps / remote reps so you don't waste cap.

I understand why you might want to do this. Losing 2 fully insured carriers wouldn't be like losing the Archon / Moros / Loki, and if you only have 2 accounts...

My guess is that you'll want sentries. The agro is all over the place and I'd bet they will wipe the fighters out. Pull sentries if they get hit, and then throw them back out. You might still lose some but oh well. Optimal is 35km to 40km. You will be surprised how long it takes.

With the traffic in w-space these days though, you'll want to do it during off hours.

If you try a achron / loki / moros, you should know there are a couple modifications to Miton's guide. The loki uses the boosting sub (for web range) so it's not as tanky. It uses vampires to siphon off the carrier (mix of small and medium), because the carrier drops a cap transfer for an armor boost. My setup was minimum pimped and mostly level 4 skill, so you should be able to make it less almost-going-to-die but I'd still recommend as many name reppers as you can afford.

i would suggest a dread and carrier, you can do 2waves in 1 siege cycle and it will take so much less time and be so much more profitable.

the dread needs somewhat high skills for it to work like t2 siege and so on

Sorry yes that is the correct inference. If you can do 4, use the fourth as a booster. The armor resist boost from the archon will be weak and higher resist will give your moros more time, plus your archon pilot can train other stuff besides boosting.