If were talking a residential home, how deep can they be. Before you cut them short, cut them long. Tap them with a hammer to loosen, you may get lucky and be able to pull them out. If this fails, then cut them flush.
A steel I beam would give you the most head room. If you want one sized, go to your local steel supplier. Most have an on site engineer who can size it for you. You will have to give them the span and load details. They will also figure a price with delivery if needed.
If the water in the trap is evaporating, fill the trap back up with water, then put a small layer of cooking oil on top. This should keep the water from evaporating and sewer gas from getting in.
I would start by putting In a dehumidifier.
https://www.homedepot.com/p/GE-50-Pint-Dehumidifier-with-Built-in-Pump-for-Basement-Garage-or-Wet-Rooms-up-to-4500-sq-ft-in-Grey-ENERGY-STAR-APHL50LB/322155488
You want to transition just below final grade. Let's say your first two courses are 12" block, your third course would be 8" block. This leaves you 4" for your brick veneer.
You also could use a union to join your pipes.
https://www.247garden.com/3-4-pvc-union-sxs-socket-fitting-for-sch40-sch80-pipes.html?gad_source=1&gclid=Cj0KCQjwh7K1BhCZARIsAKOrVqH1QSUU-Z767G7TlaNx0_zrhdO_xATZXMKmHNe5UZNm_aIHZ7N-yDQaAi3aEALw_wcB