Humans were cleansing with soapwort back in the stone age, so likely were in ancient Greece too. I suspect most of the oils listed in the OP were not used until relatively recently, have you tried extracting the oil from grapeseeds without modern machinery? If you want to be authentic use oils and butters that can be extracted using traditional 'cottage industry' type methods and contain fatty acids that can 'nourish' the scalp or hair - olive, palm fruit, shea butter and coconut oil for example. Mineral oil and petroleum jelly will just build up, not penetrate.
2a-2c, medium texture, porous/ colour treated. Three years CG, growing out mechanical and chemical damage = breakage and very high porosity. Past armpit length heading for waist.
Treatments: Komaza protein, Komaza Matani, coconut oil with sugar syrup. Hairveda Sitrinillah
Leave in: Fructis Sleek & Shine (old), Gliss ultimate volume
Styler: Umberto Giannini jelly, Boots curl creme, Rockin RInglets
Experimenting with: Mega-Tek, Curl Harmony reviver, Elvive Full Restore 5.