This post follows the previous post in regards to removing the cleric from LotFP without removing cleric magic. It has additional information to make it more useful for your game in question. I did rename the schools of magic to fit with an early modern flair as well.
True Miracles: Caster must be lawful
Kabbalah: Caster must not be chaotic
Hedge Magic: No alignment restrictions
Faerie Magic: Caster must be neutral
Necromancy: Caster must not be lawful
Demonology: Caster must be chaotic
So, part of having cleric's be just magic users who stick to lawful spells would be to figure out where to get their spells.
True Miracles - The Bible. Easily available and often memorized. This means any lawful magic-user can stop by any church and memorize any miracles they want. The bible is easily available and it is perfectly acceptable to have on you. If anything it is a sign of your character. This means a lawful magic-user can cast spells by reciting appropriate passages of scripture.
Sample Grimoires: The Bible
Kabbalah - These are the texts of religious mystics. Kabbalah is a catch all term, but this would be later Kabbalic practices when it moved away from merely being a school of thought in Judaism and entered Christianity and occult circles. The presence of Enochian languages would reside here. These texts would be available in religious libraries (such as remote abbeys) and could be legally owned. They may arouse some suspicion from the uneducated, but no inquisitor would hold these as any evidence of wrong doing against a PC by themselves. There may be restrictions in accessing the books from a purely monetary standpoint (books are valuable and monks may not want PC's getting their grubby fingers all over them and leaving smudges).
Sample Grimoires: The Hekhalot, The Book of Jubilees, The Eight Gates
Hedge Magic - Folk remedies, alchemical treatises, and ancient philosophical texts. These texts would be available in some prestigious libraries and universities, but most would be in the hands of private individuals and they would be unlikely to share and expensive to buy from. Unless the individual possessing these texts is in high repute, their possession may cast doubts onto the owner's intentions with church authorities.
Sample Grimoires: Picatrix , The Corpus Hermeticum, Turba Philosophorum
Necromancy - Dubious texts, often banned or tightly controlled. Often created by suspicious individuals who explored heathen cultures. Many (sometimes all) of these texts are considered heretical. These texts are found in ancient crypts, the libraries of illicit individuals, and only in the most secure (and often secret) of church collections for use in formulating defenses against witchcraft. Only those with express written permissions from church or king would be allowed such texts. Some court magicians would be granted access under the watchful eye of the church.
Sample Grimoires: The Lesser Keys of Solomon, Book of Dzyan, Book of Thoth
Demonology - Prehuman relics or transcriptions of extradimensional beings. These are all considered heretical by the church hierarchy, but ironically many are just considered laughable gibberish and insane rantings by the lower echelons of the church. Few works are well known enough to be recognized instantly as a danger. The church keeps it this way because the sheer fact that some of these spells work calls into question the entire spiritual foundation of the church. These are found in ancient ruins, church bonfires, and in the hands of dangerous individuals.
Sample Grimoires: The Necronomicon, The King in Yellow, Unaussprechlichen Kulten
Faerie Magic: These texts are often hidden. They are rare and while opposed by the church they will often be left intact as historical relics. The belief systems behind them having been long ago discredited as a serious threat to the church with the abandonment of the old gods. These spells are found scattered in lonely places, and in small towns viewed as quaint by the powers that be. Usually regarded as harmless folk superstition. Possession of these works is more likely to end up costing your reputation and labeling you as a quack than a witch unless there is an active witch hunt or other hysteria affecting a region.
Sample Grimoires: The Book of Merlin, Inscriptions on ancient stones, The Faerie Queene (unedited edition)
Merrow Mermaid Specimen
7 hours ago