So my house has concrete walls and ceilings. There a few places i would need to remove some large holes like for vents or light fixtures. I was looking at a concrete hole saw which seems to be a good idea but im not sure it would last or what kind of drill to attach it too. Any ideas.
Menards and other places rent core drills for large holes in concrete.
Easiest way is to call Diamond Drilling or a similar company and have them come out and drill all your holes for a few hundred dollars.
Unless you want to buy a Hilti DD100 and the bits which will cost you way more than hundreds.
Edit: Sorry I just re-read your post. If you want to cut bigger holes then you need diamond concrete saw blades for a standard circular saw. They will wear down so you could start with 1 or 2 and see how far that gets you. Depends on how many holes you want to make. Hopefully they are available in Ecuador.
Or you could order one like this.
Then you will need a sledgehammer, wedges, chisels, and lots of muscle.
The diamond core drilling bits like you linked will go through concrete and rebar, but it will need water to go through rebar. The rebar will heat up the bit and ruin the diamond without water cooling.
They are made for use with a special drill, a core drilling rig, which usually has a 5/8" threaded attachment (like a grinder) rather than a chuck like a drill. It's not a simple setup or procedure. The equipment and the bits are expensive.
I wish I knew and easy way to get through concrete with rebar, but I don't think there is one. These core rigs sell because they're what work, if there was an easier way they wouldn't make them!