What I want to know:
Are both mod chips mentioned above available in a complete solderless solution? (Product links are welcomed).
Yes, for the most part. Some people who have had issues may need to solder the J points.
Do any of the mod chips mentioned above have any known issues/bugs I should be aware of?
This thread might help -> [Only Registered Users Can See Links. Click Here To Register]
Once my Wii is modded with one of the mod chips mentioned above can I install HomeBrew stuff without the Twlight hack?
Only if you have 3.2 Wii Frimware, then you can use the DVD iso to install HBC, if you are at 3.3 then you have to use the special TP hack.
Anything else I should know before I mod my Wii? Does online play still works? Can I still buy stuff with Wii points? etc...
Yes, online works, and use wii points to purchase. Also Keep reading these forums for any new news and developments.