What are the best archers followers

So here's what I know you can do (name followed by the quest you should start but not complete):

People

• Any normal follower (or, hey, Aranea Ienith can summon an atronach)
• Delphine + Esbern - Alduin's Wall (Esbern can summon an atronach)
• Brother Verulus - The Taste of Death
• Mercer Frey - Speaking with Silence
• Thonnir - Laid to Rest
• Avulstein Grey-Mane + Geirlund + Vidrald - Missing in Action (the latter two should join you and Avulstein at Northwatch Keep)

Animals

• Meeko (Meeko's Shack) or Stray Dog (random encounter)
• Barbas - A Daedra's Best Friend
• Horse (better yet, Shadowmere)

Summons

• Two summons (with 100 in Conjuration and the Twin Souls perk). Some dead thralls can summon atronaches, so that gives your summons one summon apiece.

which brings the total to you, nine people, two dogs, a horse, two dead thralls and four atronaches. That's 13 permanent and almost everywhere (excluding atronaches and the horse) and 18 potential. This seems pretty hypothetical and I haven't done it myself, so feel free to correct me.

Other

There's also supposedly a glitch (patch status unknown) where you can dismiss your follower, hire someone else, then immediately return to your follower and rehire him or her. I don't know if people use it with the Dark Brotherhood Initiate(s) for a reason or because it only works with them.

Also Odahviing.

In the vanilla game; no.

With mods; possibly, depending on the mods that are out there.

Basically there are "Build-types" with the AI in the game, that lean towards certain traits in the character skill tree. Strength, Sneaking, Magic, etc. Lydia is a Strength/Melee character type, therefore she would prefer to use melee weapons.

That being said, if you give an AI a weapon of greater damage output, they will prefer that weapon. So if you take any high-damage melee weapons away from her, and give her a high-damage bow instead, she will prefer the bow. However, with the AI the way it is, this does not have very much functionality, as she is primarily a melee AI, so she'll tend to whip out her sword and swing that around anyway.

So if you want to achieve this, mods are your best bet.

EDIT: You could try using commands, or pickpocketing her to remove her base equipment, leaving her only with her bow and arrows. However, should you give her a melee weapon to carry, she will likely use that instead.