First we need to extended rich rendering of bech32 entities beyond npubs to events. this is tracked in:
nostr:note1rs5shxk8ems0d878tymvntej4zcv4rvg7ntcpac5539xrcvvntss2vqxds
Then we need to enable launching unsupported events in other applications. Perhaps NIP-89 would be better than hardcoding my favorite client (eg wikifreepedia) for each kind?
Your 2) is a good idea. There are some some interesting UX options for when note recommends viewing a nostr event in a particular client by linking directly to it.
I'm not sure about 3). Wont it be clear from the context that it is the wiki landing page for the repository?
PS: I just created a NIP-89 application handler for gitworkshop.dev. nostr:naddr1qqxnzde3xc6rvv3n8qun2v3eqgs2qzx779ted7af5rt04vzw3l2hpzfgtk0a2pw6t2plaz4d2734vngrqsqqql8ky0uzvz
you can recommended for nip34 event kinds here: