Does election apply to the angels? Do they have freewill?
Yes, election did apply to the angels, there are verses that explicitly state that there were elect among them.
Let's define "free will" so there isn't a misunderstanding on our part:
God has endowed human will with natural liberty and power to act on choices so that it is neither forced nor inherently bound by nature to do good or evil. (Matthew 17:12; James 1:14; Deuteronomy 30:19).
Humanity in the state of innocence had freedom and power to will and to do what was good and well-pleasing to God (Ecclesiates 7:29). Yet this condition was unstable, so that humanity could fall from it (Genesis 3:6).
Humanity, by falling into a state of sin, has completely lost all ability to choose any spiritual good that accompanies salvation (Romans 5:6; 8:7). Thus, people in their natural state are absolutely opposed to spiritual good and dead in sin (Ephesians 2:1, 5), so that they cannot convert themselves by their own strength or prepare themselves for conversion (Titus 3:3–5; John 6:44).
When God converts sinners and transforms them into the state of grace, he frees them from their natural bondage to sin (Colossians 1:13; John 8:36) and by his grace alone enables them to will and to do freely what is spiritually good (Philippians 2:13). Yet because of their remaining corruption, they do not perfectly nor exclusively will what is good but also will what is evil (Romans 7:15, 18, 19, 21, 23).
Only in the state of glory is the will made perfectly and unchangeably free toward good alone. (Ephesians 4:13).
Chapter 9 of 2LBCF
So did they have free will? Some were on a conditional footing as that of Adam, while others an unconditional, in my humble opinion that I share with others. I don't know the details, simply because, they aren't mentioned in detail in Scripture. Where Scripture is silent, we must be silent.