Yes, you will need to break up the floor for both the drains and the pit for the sewage pump and tank. Both the tank and the new fixtures will need to be vented. The vents can be tied together above the sink level (normally about 42" above the floor) so you won't need more than one vent leaving the area. You will want 1/4" per foot slope down into the pit for the drain lines, and they need to be sized appropriately. You probably don't want to make huge holes in the slab, so rent or pay someone to use a wet saw to make some neat cuts where you want them, then break out the concrete, lay the pipes, and then backfill. The shower should have a 2" drain, and the toilet 3 or 4". Some places require all drains under the slab to be some minimum, so the sink drain may need to be bigger than 1-1/2", at least in the slab.
Try drawing to scale where you want things, then see how it would work out. You can post a drawing here for comment.