You've opened 1-of-a-suit but don't have a minimum (about 12-14), but neither do you have a maximum (about 18-20). You have to choose a rebid. With that in-between range, opener won't have a balanced hand (would have opened 1NT with 15-17 balanced). So, your possibilities are: 1) Jump rebid your suit (6+ card suit, roughly 15-18 in playing strength) 2) Jump raise your partner (4-card support, roughly 15-18 in playing strength) 3) Bid a new suit (very wide range). For 1-1-2 you could have a dead minimum, but could have up to about 17 or 18 (because 1-1-3 would be GF) .
Note: In #3, "Bid a new suit" does not refer to a jump shift (GF) or a reverse (forcing one round).
AQ76
AQ54
KJ43
2
What is your rebid after you open 1 and partner responds 1?
1
2
2
3
4
4
3. No need to mention spades--you already have found your 8+ card fit. You are too strong for only 2, but not strong enough to do more than invite with 3.
AQ765
AKJ3
Q43
2
What is your rebid after you open 1 and partner responds 1NT?
Note: It doesn't matter how you play the 1NT response
2
2NT
3
Other
2. You don't have enough to jumpshift to 3 (game forcing).
AQ76
A2
KQ10765
J
What is your rebid after you open 1 and your partner responds 1?
1
2
2
3
Other
1. You must show your major, but you aren't strong enough to jumpshift to 2 (game-forcing).
A2
KQ108
AQ108762
--
What is your rebid after you open 1 and partner responds 1?
2
2
3
3
2. You have only 15 HCP, but this hand is worth much more. With a void, a great 7-card suit and a fitting honor in partner's suit, you are worth this reverse. It is forcing 1 round (not to game). It shows 4 hearts and longer diamonds and a good hand. I can't think of a more accurate description. A jump rebid of 3 would show similar strength, but is less descriptive than 2 which also tells the story about the 4-card heart suit.
K2
KQ73
K2
AJ543
What is your rebid after you open 1 and partner bids 1?
1NT
2
2
2NT
3
I wouldn't open 1
Other
I wouldn't open 1. You sometimes have to look ahead before opening. I don't love opening notrump with two doubletons, but you need to consider a rebid. I wouldn't open 1NT with a five-card major and a four-card minor, but with this shape you have a no-win rebid problem that you could have easily avoided by opening 1NT.