Miho, here is the explanation about the comment

Hello Miho. Thank you again for correcting my Japanese. I think that the particles も、が、は、を、に、and で are difficult to understand. I think it is probably the same for things in English such as: is, the, were, too, to, where, may be, maybe, there, their, etc...

I should probably explain what my uncle wrote (since his computer is slow, I don't think that he checks the internet that often). I should probably say that what my uncle wrote is probably very difficult for non-native speakers of Enlgish to understand (and maybe even native speakers of English who are not from Texas, because of the southern dialect).
I think that you understood a lot of if (you understood that miho is short for friend in Tex-Mex).
I should explain Tex-Mex. Because Texas is so close to Mexico (in fact, it use to be a part of Mexico a long time ago), there is a lot of Mexican and Spanish influence. Tex-Mex kind of refurse to those things that are influenced my Mexico and Spain from the past (although we are not of Spanish or Mexican lineage).
This next part will be difficult to understand, but I will try to explain.
He said that your name "Miho" is short for "Amigo," which means friend (I think you understood that part). But, he was using your name as a "play on words"。 僕の電子辞書によると "play on words"の意味は「ごろ合わせ、しゃれ、地口」。 It's sort of like a word game.
About when my uncle said, " Oh,by the way Ben, Miho says she is always looking for ideas to paint?Give her American words she does not undestand and ask her to paint what she thinks they mean.Then, tell her what they mean and do the same." He really didn't mean anything by this, he is just making a joke. Obviously he does not really mean that you should take the time to paint what you think a word means.
When my uncle speaks, he is not always serious. I think that it must be very difficult for Japanese people to understand when English speakers are serious and when they are joking. When I try to speak the same way in Japanese that I speak in English, Japanese people think that I am serious when I say outrageous things (although I am just joking). In English, usually what I said would have been funny, but in Japanese it is strange. Since there is not equivalent way of speaking in Japanese, I think that my uncles English must be very very difficult for you to understand.

I will try to explain a little in Japanese of what I wrote:
僕の伯父の文には説明したいけどちょっと難しい。テキサス弁から英語にもちょっと難しい。　じゃあ、伯父の文：「Me and my buddies always say "hey miho" when answering the phone with eachother. MEANING----miho is short for migo,which is short for amigo,which is Tex-Mex for friend!!」。あの文には美帆ちゃん分かったと思う。
伯父の文：「Oh,by the way Ben, Miho says she is always looking for ideas to paint?,give her American words she does not undestand and ask her to paint what she thinks they mean.Then, tell her what they mean and do the same」には実は意味がない！！　冗談だけ。だけど、いちじ一句の意味は「ところでBen、美帆ちゃんは絵のために新しいアイディアが探しているといった？　じゃ、もしBenはMihoに知らないのアメリカの言葉調べたら、Mihoは分からないの言葉の意味油絵の紙で推測の意味描写して、そのあとでBenはMihoに本との意味説明したらいいと思う」。説明はまた変けど。。。ごめん。まだ日本語で説明できない。 I tried to explain the meaning a little, but I don't think it was that helpful. I hope you understand a little better at least. Anyways, talk to you later.

Also, to anyone who reads this, the next article will be up in a few days. At the last minute, I went with a few friends to a safari park near Mt. Fuji (I also took a lot of pictures). I plan on doing an article about that in a few days.
Later.