How did Aquinas and Reformation-era Protestants disagree on God's will?

The quote you gave first was not actually from Aquinas but was from Boethius. I cannot find anything on Aquinas but here are some points Boethius and Damascene made in that source - but note conclusion 8.

In Article II – God’s Will, “Boethius says that God ‘beholds all things in a single look of His mind.’ In like fashion, then, with one simple act of His will He reaches out to everything which He wills; and so antecedent and consequent should not be affirmed of His will.

7. God knows things in Himself and in their own nature; and although they are in their own nature only after being in the Word, even so the distinction of antecedent and consequent is not affirmed of God’s knowledge. Then neither should it be affirmed of His will.

8. The divine will, like the divine existence, is measured by eternity. But the duration of the divine existence, because measured by eternity, is all simultaneous, having no before and after. Then neither should antecedent and consequent be placed in the divine will.

To the Contrary

l. Damascene says that it should be noted that “God wills all to be saved by His antecedent will,” and not by His consequent will, as he adds just afterwards. The distinction of antecedent and consequent therefore applies to the divine will.

2. There is in God an eternal habitual will inasmuch as He is God, and an actual will inasmuch as He is the Creator, willing things actually to be. But this latter will is compared to the former as consequent to antecedent. Antecedent and consequent are therefore found in the divine will…

[Answer /conclusion] 8. Antecedent and consequent are not affirmed of God’s will for the purpose of implying any succession (for that is repugnant to eternity), but to denote a diversity in its reference to the things willed.”

Frankly, I’m not any further forward with such philosophical points. But it’s clear that all Christians, at all times, have protested at trying to speak of God’s will in terms akin to how the pagans viewed the volatile wills of their capricious deities. This is where common ground is to be found:

“Most often, impassibility simply meant that God is not like the pagan deities, which were little more than exalted human beings. Determined by their passing whims and passions, the gods could without notice range from beneficent aid to benign neglect to a drunken rage. Slaves of their lust, greed, and power, they could also exhibit virtue on occasion. They were generally capricious and unpredictable.” (Pilgrim Theology, p80, Michael Horton, Zondervan 2011)

Not so the God of Christianity! Here is a Reformed Protestant explanation of God’s will:

“All of God’s acts are consistent with his nature. God determines the world’s course; the world does not determine God’s course. As Gerald Bray observe concerning the patristic doctrine of impassibility, ‘The emphasis was not on tranquility in a state of indifference, but on the sovereignty of God.’ So when the Westminster Confession says that ‘God is without parts or passions’, it is not denying God’s responsiveness to creaturely actions; rather, it is denying (a) that God is ‘made up’ of various faculties or emotions and (b) that God is taken captive by anything other than his own nature. Like Greek apatheia, Latin impassion means ‘nonsuffering’, in the sense of God’s not being overwhelmed or overtaken by something external to himself… If he were determined in his very being by what we do, then we would have no confidence that he, like Zeus, might not as easily destroy us in a fit of rage as weep helplessly over our condition.

God’s word reveals his promises and commands, as well as his actual execution of judgments and deliverance. However, his eternal plan includes everything that happens, although not revealed to us.” (Ibid. pp77-8)

The Heidelberg Catechism, q.1 in Doctrinal Standards of the Christian Reformed Church says, “Not a hair can fall from my head without the will of my Father in heaven: in fact, all things must work together for my salvation” [referring to Romans 8:18. This passage does] not say that God does all things or that all things are good, but that he works all things together for our good – which means, ultimately, for our salvation [to those who are called].

There is a distinction between God’s hidden decree and his revealed will. …This distinction between things hidden and things revealed is maintained throughout Scripture (Dt.29:29; 1 Cor.2:7-10). Although God has decreed everything that comes to pass, he has not revealed everything that he has decreed. We must not try to figure out God’s secret providence, but respect his majesty (Ro.11:34) and attend to the means that he has provided for our salvation (through word and sacrament) and earthly welfare… So we are directed to seek out God’s will only in that which he has revealed.” [See Calvin, Institutes, 1.17.2]

Then the idea that God has “a perfect will” which is “Plan A” – His best for our lives – but there’s also a “Plan B”, is exploded. “It’s comforting to know that God’s “Plan A” is sure to be realized because God is working everything – even our sins and mistakes in judgment, as well as external threats and calamities – together for good. We never have to fear falling into “Plan B”. (Ibid. pp.115-6)

Answer to your question: There are various points of agreement between Catholic and Protestant schools of thought on God’s will. The differences seem to arise from Aquinas & Co. delving deeply into philosophy, to try to thrash out a form of words to account for difficulties arising from our limited understanding of God, while the Reformers drew the line and did not delve into philosophy. They had a sort of “Thus far and no farther” theology of God’s will, bounded by what the scriptures actually said. They did not try to probe into even why God had a hidden will, but to note it, and satisfy themselves with the task God has given Christians, of discovering his revealed will, and then doing it.