Complementing mason's answers:1. I have "Intel Corporation HD Graphics 630 (rev 04)" (according to 'lspci' and went through the issues you mentioned when I was using Trisquel 7's X server (the latest kernel made no difference). There is no such problem with Trisquel 8.
4. You may (or not) want to use the NetInstall, if you do not plan to use the default MATE desktop environment (and do not want to have two applications for a same task).
Welcome! :-)
