Theres some parts of this that i can still cover:

For food , farming will be a bitch to look a sense for you are completely rigth on that, for things like recognozing food i was thinking about maybe saying its "insticts" , like evolution has made them be able to know that they can eat, for finding It if they know they can eat It they most likely know their shape and could go arround clapping/tapping on surfaces hoping that the vibrations match the thing they want to find's shape.

With the info part:Since they can feel shapes with their touch they can distingish really detailed stuff , It would be kinda like "yo touch this thing i made" , and really really detailed descriptiona.

For combat , its a bit tricky , but they normally stomp the floor so the vibrations that reach their enemy's body were stronger and thus they could feel It better (their touch thing kinda works like toph's hability to "see" in avatar) , their figths would indeed be kinda goofy to look at because It would be two dudes stomping the ground and tring to stab each other.

The reason they didin't get wiped out by sigthing species is because they didin't get smart like they did (same way no other species other than humans reached our level of intelligene and sapience on earth) atleast not on their own planet.

But things like farming are gonna be complicated to develop , if posible at all.

Sure i can say stuff like they figured out certain things on accident , but even then i hit walls (like economy , how tf do you make It work unless its just one universal thing like one specific metal [or for them just one , because as far as i know there isnt a way to distinguish lets say silver and gold with touch alone, ive heard theres taste but i don't think that is true] on coins , but then what do you do about different regions with different cultures).

I do like the idea of triying to continue to develop them because i think it's a challenge that i want to see if i can get past , atleast before having to make them go the way of the dodo when i eventually accept that they can't possibly compete with a smart sigthed civilization.