You’re right. ”Egen” is an exception to this rule. However, you’ll hear many people saying ”mitt egna” in everyday speech.
If you insert another adjective before it, you’ll say ”egna” as a normal adjective:
- Min egen lägenhet. (My own apartment.)
- Min första egna bostad. (My first own apartment.; you can never say ”min första egen”)
If you put an adjective after it, both are acceptable.
- Min egen teori. (My own theory.)
- Min egen/egna lilla teori. (My own little theory.)
Yes, it works for all pronouns, and it doesn't change: Du äter ditt eget äpple 'You're eating your own apple', Han äter sitt eget äpple = 'He eats his own apple'.
In the latter case, you can't be sure whether the English his own is a replacement for sitt or not, so you'll only ever be able to tell from context if He is eating his own apple means Han äter sitt äpple or Han äter sitt eget äpple.
Edit: I meant it doesn't change depending on person, of course it changes depending on gender and number: du äter ditt eget äpple, din egen apelsin, dina egna päron 'you eat your own apple, your own orange, your own pears'. But it's the same for all persons.
Yes, but that general rule only applies if the 'g' is the the first letter of a word, like in 'get' ('goat'), 'gissa' ('guess'), 'gyttja' ('mud/sludge'), 'gäss' ('geese'), 'göra' ('do/make') etc.
When 'g' comes inside a word it mostly becomes soft if it precedes a soft vowel but there are many exceptions, especially if it is a word of non-Swedish origin (like 'agent') or has the emphasis on the vowel that precedes the 'g'.
A good example could be 'égen' vs 'egéntligen' ('really/actually') (I write it with 'é' only to show where the emphasis should be). 'Egen' has a hard 'g' but 'egentligen' has a soft 'g'. Hope it clarifies a bit!