Are these homebrew 'Enhanced Arrows' balanced against each other?

Question

Between adventures my campaign has Down Time, a more structured form of play where the players can build relationships with other NPCs, create things, earn money, etc (taking inspiration from the Blades in the Dark system). The players can do 2 'activities' for each Down Time, allowing them to complete a portion of a task, discover something new, etc. for each activity.
The party's Artificer/Ranger, Art, is looking to create arrows with additional effects. I came up with this list of arrows, with a few restrictions listed below. I'm not concerned with whether giving Art these arrows will unbalance them vs the other party members as everyone is able to gain powerful things through their Down Time, but more whether the arrows are balanced against each other. the intention is these are close to cantrips or 1st level spells in power, with a few at 2nd or 3rd level that they gain access to at higher levels.

• You can spend an Activity to invent a new arrow head, at the cost of 50 gold; roll a d6 on the table below to determine which arrow has been invented. After level 9, roll a d10. Reroll if the arrowhead rolled has already been invented.
• Invented arrowheads can be produced during Down Time, without using an activity.
• You can make and hold up to 4 [(proficiency bonus+INT)/2] arrows at a time, paying the cost to make each arrow.
• When applicable, the Arrow DC = 8 + your Proficiency Bonus + INT.
• On your turn, as part of the attack action, you can fire an Enhanced Arrow. Make a regular weapon attack roll, and add the extra damage to the attack on a hit. You can fire one enhanced arrow per turn. on a miss, the arrowhead shatters on the ground harmlessly, unless otherwise stated.

d6-d10	Arrow Type	Extra Damage	Effect	Cost
1	Flaming	+1d6 Fire	Target is lit aflame; it takes 1d6 fire damage at the start of its next turn, and can make a CON saving throw to end the effect at the end of its turn. The target or another creature can also use an action to pat the flames out, ending the effect.	25 gold
2	Icy	+1d8 Cold	The Target's movement speed is halved until the end of it's next turn.	25 gold
3	Splash	+1d6 Acid	The target and each creature within 5 feet of the target must make a DEX saving throw, taking 1d6 acid damage on a failed save. This effect applies even if the attack misses.	25 gold
4	Accelerated	+1d6 Lightning	In a line 30 feet long and 5 feet wide from you in the direction of the target, each creature must make a DEX saving throw, taking 1d6 lightning damage on a failed save. This effect applies even if the attack misses.	50 gold
5	Booming	+1d10 Thunder	If the target moves before your next turn, they take 1d10 thunder damage.	25 gold
6	Necrotic	+1d8 Necrotic	The target cannot be healed before the end of your next turn.	25 gold
7	Bolas	Half the weapon's damage	The Target must make a DEX saving throw. On a failed save, the target is restrained and falls prone. The target or it's ally's can attempt to break the restraints with a Strength (Athletics) check against your Arrow DC or cut through the restraints (10 AC, 2 HP), ending the effect.	75 gold
8	Sickening	+1d4 poison Damage	The target must make a CON saving throw. On a failure, the target becomes poisoned for 1 minute, and they take 1d4 poison damage at the start of each of their turns. They can repeat the saving throw at the end of each turn, ending the effect on a success.	50 gold
9	Glaring	+1d8 radiant	The target must make a CON saving throw. On a failure, the target is blinded until the end of your next turn. This effect applies even if the attack misses.	75 gold
10	Seeking	+3d6 Piercing	Attacking with this arrow is always done with advantage, and ignore the long range penalty. If the attack misses its target, it can be made again against a second creature that is in a cone behind the target, out to your weapon's long range.	75 gold

Edit to add: The other players have access to a similar gold-to-power system. The Rogue can spend to create poisons, the druid spends to train familiars with additional abilities, the paladin can imbue holy artifacts with temporary power, etc. The costs are similar, with single use objects being in this price range, and continuous powers being more expensive or having smaller effect.

The assistance I'm hoping for:

1. Should the extra damage be changed for any of these to balance them?
2. Should the cost be changed for any of these, relative to the other arrows? (The party has enough gold currently that these costs will not be prohibitive prices, but will stop them from being fired at every encounter available)
3. Should using the arrow take a bonus action, instead of just being a part of the attack action?
4. At level 9, Should I increased the damage of arrow 1-6, to keep pace with the stronger arrows?

Answer 1

Try getting a better balance between damage and other effects.

1. If the arrows have a substantial crowd control effect or debuff they should do less, or even zero extra damage (#2, #6, #7, #8, #9). Or increase the damage of others to ballance.
2. Yes, cost adjustment is needed. Cantrips are okay at 25gp, but the 1st level ones should be closer to 100gp, and 2nd level about 250gp. You need to consider that these are superior to the cantrips and spells that you might use a scroll (consult scroll price table in Xanathar’s Guide to Everything, page 133) or a spell slot for as you get to add it onto an attack, making it especially potent if you have more than 1 attack per turn.
3. Using a bonus action is a tough call, while it would ensure they only use one arrow per turn, there's not a really good justification in the mechanics, and there are a lot of other things (like hunter's mark) that they may want to be using. It might just be cleaner to say that you can only use one special arrow per turn.
4. If you allow for multiple special arrows to be used in a single turn, no, don't increase the damage, they'll get the increase from their extra attack. If they can only use it once, then let those scale similar to the way the cantrips do.