It's a YES to graphics card and a NO to core i5 processor. T3500 was shipped with 525w power supply, it could handle graphics card up to 140w.  A GTX 1650 requires 75w, and it will get power from PCIe slot.  So, it's a YES. Precision T3500 supports Intel Xeon 3500 or 3600 series processors.  It does not work with Intel Core-i processors.  So, it's a NO. Here is a complete system specs [URL]  
Hello! I was recently gifted a Dell precision T3500 gifted to me by a friend, I want to earn money over the summer to improve it, I want to make it a mid/ lower range gaming pc. I first of all want to get a used GTX 1650 4gb as the graphics card for the system, it should work out based on the power supply but do correct me if I’m wrong (I’m incredibly new to this) I have the same processor it came with but I want to know if I could upgrade to a i5 vPro I got from another pc I had lying around  these are the main 2 upgrades I want to make, I’m not quite sure it is possible but I’d love to hear what all of you think, thanks for reading. 
Dell precision T3500 gaming upgrades