Check any fuses on the dash or any that may have been added in the wiring by the PO.
Pick one item that is not working (blower) and try to troubleshoot that item only...you may find one issue and that may the cause of everything else.
Blowers are around $40 or so, Bilge Pumps are expensive if you get a bigger than stock one like I installed...think it was around $70.
Guages are a hit or miss on prices...check ebay...saw some go for $100 for all vs. other adds that were at the $450 mark.
Pull the old stereo out and start from scratch...that's is what we did on the 190 we bought last fall...no clue what the guy was trying to do except add hours to the tach.