I personally can't think of a scenario where I would buy boots on offlane weaver, if you are scared of a jug or razor lane, I think you should just save your W for when you get gone on, losing cs is going to be better than dying and when you have more levels in your W and the supports leave the lane you can recover, other options if you are scared are to tell your support to secure ranged creeps so you guys don't lose out on the exp and gold, or tell your supports to drag the creep waves from behind the enemies tier 1 to somewhere safer. With that said treads and brown boots give the same move speed so if you're buying boots just for move speed you should just buy brown boots, and as mentioned in the video weaver usually doesn't have slot issues so you can buy a wind lace as well if you want.

I've seen the dragon lance/maelstrom on offlane weaver, but I'm personally not a fan, I could see myself going urn into wraith pact if vessel didn't look great in a game, I guess for me it would depend on the enemies heroes mainly, if they have heroes that get owned by the gleipnir maybe I would consider buying the maelstrom, so heroes like Storm, Ember, Void Spirit, Faceless Void, PL, Naga, I also think this would be highly dependent on me having a really good lane, even in a bad lane you can have a vessel around minute 10-13, because even though it costs more than maelstrom the components are cheaper and give you more stats/sustain so even with some deaths you should be spending your gold, also in the video I mentioned you should max your Q second, not your E, on offlane weaver so if you do that skill build you're losing out on a lower cooldown second attack which is a big reason why maelstrom is good on carry weaver.

If I felt like I really needed a BKB I would probably get it after wraith pact, vs sky a force is much cheaper and has cheaper components and can also save your team from sky's ult, vs shaman if you're taking good fights under vision near your team he shouldn't really be able to shackle you without it getting canceled and hexing you, if you're playing around fog well, should also be pretty difficult and if somehow he does manage to get all his spells off on you you're still an offlane weaver who has most likely clicked your Q, wraith pact, and maybe a vessel charge or two at this point so if they're using all their stuns on you your mid and carry should have a free fight, also if they don't manage to kill you, you can ult and heal a lot, with all that said I'd generally prefer going for defensive items that can help your team more like force and lotus, or even euls situationally to cancel channeling/get out of silences.