I know how to properly install a concrete countertop and proper thinset and subtrate for stone as opposed to say ceramic. 

. $25k sounds like a lot, but when you install new roofs, HVAC systems, hot water tanks, ceramic tile, new supply lines to angle stop valves, vinyl plank flooring in high traffic areas, carpet in bedrooms, faucets, fixtures, electrical panel updates, etc. it really is not that much and important if you plan on a long term hold.

I also plan on having the flooring redone from ceramic tile to laminate floors.First off, what are some important questions that I should ask the contractor my friend recommended?

have went to ceramic tile everyplace but bedrooms and carpet in bedrooms. will see how this works. 

And always ceramic tile . 

January I will start tearing out old fixtures in the bathroom, refinishing the tub and laying backerboard and ceramic tile.

From what I understand, with some of those retro colored bathroom tile jobs, there are companies that can paint the ceramic rather than ripping it all out and starting fresh, for a fraction of the price of an overhaul.  

or ceramic tile?

I have ceramic tile floors throughout the apartment, regular white latex-painted walls, and drop ceiling tiles on the ceiling.

And just to be more ambitious, this is the list of everything I want to do:- Clean all the junk and debris from the house and yard and demo the shed in back- Replace the roof and fix the gutters/soffits- Landscaping- Replace all the windows with double-pane vinyl windows- Replace all the floors in the house (ceramic tile for the kitchen/bath/laundry room, and vinyl plank for the living room and the upper level)- Re-do the bathroom with new everything -- plumbing, tub, shower surround, floor, sink/faucet, toilet, mirror, accessories- Re-do the kitchen with new cabinets, counter tops, and sink/faucet- Paint the entire interior (white ceilings, beige for walls, white for trim)- Replace all the light fixtures, outlets, and switches- Replace the front and back doors and put in new locks- Add smoke detectors and carbon monoxide detectors as required- Finish off the upper level (that was begun by someone else)I want my rehab budget to stay at or under $30,000 and I want to complete everything within 2 months from closing.