Mostly people only comment on stuff that relates to them, pertains to things they care about or gets a good enough psychological reaction to comment. My opinion on the matter.
There's exceptions i guess, if you like the startup founder's ..the idea and feel that your contribution as tiny or as big as it may be will put this great product out to market quick, then why not drop your rates. Other than friends/family referrals, ide stick to your normal rates. You never know what your " serendipity" karma may come back to you and that small startup you helped remembers what you did for them and does something awesome for you. i dunno i guess my two cents.
unreal, sorry to hear that situation...if you solved it amicably then i'm sure it wasn't a horror story. I guess i'll hit up legalzoom or quora for the best and easiest way to trademark. If you know good site's please recommend.
idea's are a dime a dozen right? with the right team/talent within that team, execution on whatever idea you choose is what's going to matter in the end to your business and to potential investors. Great idea's have still failed and i can guarantee the multiple factors that brought that on happened because of the wrong team and incorrect assessment of product market fit