No, I don't think that TB would work well with Alpha, though TB offers burst, in a WP Alpha build, items are focused on sustained damage. Also, TB works well when trying to snowball in the early game, as the burst damage offered by TB is quite significant early on, and the "poke" nature of the early game. However, Alpha is weak early game, so TB doesn't do much as a first item, and TB loses effectiveness as the game goes on longer.

I'll admit, I haven't played Idris much yet or seen him in competitive. So I'm not 100% on him yet. But I used to main Ringo.

When playing snipers against assassins like Idris, kiting is key. The ability to move back and away while still dealing damage is important to ensure that the Idris will have a difficult time jumping you without taking damage. After basic-attacking, move a step in any direction and basic attack again. This is called stutterstepping, and it's invaluable for WP ranged heroes. It increases attack speed slightly and lets you attack on the move.

In most of the matches I play, I win the game early before I finish my entire build. I don't usually have to replace Stormcrown, but if I have enough gold, I'll go for a SG or EOH, depending on how much damage/burst the enemy has. Late game, farming isn't much of a priority, and three tier iii items should be plenty of damage for objectives and team fights.

Wow, thank you for the praise!
One piece of advice I wish a lot of new players got to hear: play as many different heroes as possible. Battle Royale is excellent to get familiar with heroes so that you know how to play a bunch of heroes and how to counter them. Also, don't get too comfortable on a "main." Sometimes, the best hero to pick isn't a favorite, but a counter or meta-pick.
I'd recommend getting a flex-pick hero, someone who can be played comfortably in the lane or jungle. Kestrel or works well, and she's strong this update, but she requires some skill to use effectively. Samuel was originally designed for the lane, but he's stronger in the jungle and requires more skill to aim his abilities. Idris and Blackfeather can fulfill lane or jungle roles, but I don't have much experience with either.