The only way I can think to do this right now is to edit all the skills you want so they have no ability requirement, learn them, and then return their ability requirements to normal. Kind of a pain, but I don't think it'd take that long to do for a handful of skills.
You'll have to get Norbyte's extractor (on this forum), unpack Game.pak (I think, or maybe it's Main.pak), and find the file Public/Shared/Stats/Generated/Data/Skilldata.txt. Open this with Notepad++, and maybe all the skills you want have "None" under Ability and Element.
For example, change:
new entry "Projectile_Silence"
type "SkillData"
data "SkillType" "Projectile"
data "Ability" "Defensive"
data "Element" "Source"
data "Tier" "Adept"
...
To:
new entry "Projectile_Silence"
type "SkillData"
data "SkillType" "Projectile"
data "Ability" "None"
data "Element" "None"
data "Tier" "Adept"
...
Put this file in your game directory/data with the same folder structure as you find in the extracted pak. You can see this in my mod, Scales, if you want a reference. (I wouldn't use my skilldata.txt unless you want my changes).
http://www.nexusmods.com/divinityoriginalsin/mods/68/?Then, you'll be able to go in and learn all the skills you don't know and they'll appear under the "Special" tab in your skills list. Once you know all the skills you want, you'll have to save and quit your game and edit the skilldata.txt again and revert all the "None"s to whatever they were before, or the skills won't scale with your stats correctly. I think this should work, but I'd just test it with one skill first to make sure it works right before you do it with a bunch of skills.
There is a line in the data.txt (in the same folder as the skilldata.txt) with the line
key "Skills Per Ability Point","2"
But I can't figure out what this does. Changing it doesn't seem to do anything as far as I can tell. It doesn't even make sense, since you can learn 3 skills for 1 point, not 2.
Good luck. Hopefully you figure it out.