Features that you've mentioned here used to be possible through using html code and then BBcode until the devs removed it to avoid security issues...
Since the update to the options available on the forum I've always been perplexed as to why they aren't also available on the league wall, or any text input on this game for that matter.
If links are ever a massive security issue, then maybe ban links outright and have a league's page and thread more integrated/connected: League threads are more special than other threads and should be treated as such. Another solution: have all newly added links up for moderator review before they work properly.
