The HDMI port is not plugged in. When you poewr on the device it boots directly, with or without hdmi. I've also entered recovery with USB keyboard with mouse on it, and it worked without issues.
For heatsink you could try putting some small plates around it or submerge eveything into liquid tape.

Due to power consumption not being so efficient + no display, I will wait for wine for android, and try to solder it somehow, see my other thread

I just picked up 4 of these from Straighttalk - https://shop.straighttalk.com/shop/en/straigh...&utm_content=10715754

They are Octacores and refurbished. However, they were free next day shipping and I used a 20% off code ( STRAIGHT20 ) at checkout. Since I went through a rebate site on top of that, I will get even more back off the purchase. 4 of them cost me just under $82 shipped.

Ram shouldn't be too much of a concern as WCG apps for Android have specs of 250MB required but don't typically use that much or at least not at all times. So, even if they did, the caching on the internal memory shouldn't slow things down too bad. But if you were to see things erroring, you could probably get away with running 6 cores. My concern is more for heat as running that many cores 24/7 at full bore will have a greater impact then running dual or quad phones at full bore. I'm guessing performance will be hindered by thermal throttling more than Ram starvation. I'm definitely gonna have to reconsider where these sit.

Going back and looking, the alcatels I run are quads with only 1GB ram, and they do not have problems with ram usage, so you should be good with the 2GB on an octo. Only thing I would worry about is if the battery is removable.

Yep I have read that some phones will not power up without the battery installed. So I tried the procedure on one device and it booted with no problems. I had been previously running them with 3 of the 4 cores enabled to keep heat down, but that only prolonged the death of the battery. With them getting direct power, I now run all 4 cores with no issues. I was glad to see that these will indeed work without a battery. My soldering skills are less than ideal, but it worked. A couple pieces of electrical tape help keep the USB cable from pulling too hard against the solder points. I put the tape up around where the camera is. If you put the tape in the battery compartment it will likely get hot from the heat of the cpu, and just eventually fall off.