Have you used any of these products solo before? It's definitely a solid stack, but it will be difficult to tell what product is delivering what benefits. You might want to consider only running 1 or 2 products so you can assess their effectiveness.
If you choose to run all 3 at the same time, I would dose it like this:
Alphamax XT - 2 caps AM with breakfast, 2 caps PM with dinner or before bed
EP1C - 30 min preworkout (per label)
STR3NGTH - 1 cap with breakfast or dinner, and 1 cap with your post workout meal
I would agree with your idea of holding off on adding the other products into this stack. More isn't always better, and these three products already pack a serious punch. If anything, I would scale it back to Alphamax XT and EP1C for 8 weeks, and then run STR3NGTH and the other products following the first 8 weeks