(Edowaado: Ore-tachi wo hitobarashi ni shite nani wo suru ki na no ka.)
オレたち (ore-tachi): is the same pronoun as before “ore,” meaning “I,” with the plural suffix, “-tachi,” making this mean “us.”
を (wo): is the accusative particle.
人柱 (hitobarashi): is the same noun as before.
に (ni): is the dative particle. You may want to say “to use us as a human sacrifice.”
して (shite): is the gerund of the verb “suru,” and it is being use conjunctively. Having said that, you will find in your translation that it will sound strange, mostly because this is a question, so you can, in your translation, make this a temporal clause by adding “when” to this phrase.
何 (nani): is an interrogative pronoun. This means “what?”
を (wo): is the accusative particle.
する (suru): is the verb we’ve seen a lot of here.
気 (ki): is a noun meaning “spirit” or “energy.” When where’s a verb phrase modifying “ki,” it will very often mean something like “a mind to X,” as in having the spirit, or drive, to do something.
な (na): is the adjectival verbal suffix we saw before. This is making the noun phrase a verb phrase because “no” is coming up.
の (no): is the substantivizing suffix.
か (ka): is the interrogative suffix. You can take this question to be rhetorical, if you wish.
Translation: “Edward: When they use us as human sacrifices, what is it that they have a mind to do?”
(Edowaado: Renchuu kara kikideshite yaru.)
連中 (renchuu): is a noun meaning “colleagues,” but it is used in an informal context to mean “these/those guys.” In this case, Edward is talking about the homunculi.
から (kara): is the post-position from before.
聞き出して (kikidashite): is the gerund of the verb “kikidasu,” meaning “to get information out of/from [someone]” It is in the gerund because it is working with the following verb.
やる (yaru): is the indicative, imperfective, affirmative conjugation of the verb meaning “to do,” which is like “suru” except the implication is that it’s a bit grittier, if that makes any sense. In shounen media, in my experience, characters will say “X(gerund) yaru” once in a while to express that they will do something that may be, on the whole unpleasant. (In this case, because Edward is basically saying he’s going to beat them up.)
Translation: “Edward: [We] will get the information from those guys.”
エドワード (Edowaado): is Edward.
君 (kun): is an address suffix used for young boys. I’ll note here that those who want to speak Japanese should, for safe measure, stay away from imitating the address suffix patterns in anime. In real life, as I understand it, young boys refer to one another as -kun without any major problems, young girls can refer to boys they don’t know well as -kun, but young girls, much less young boys, don’t refer to one another as -chan unless they’re close like that. So, if you need to call anyone, stick to -san unless they’re a teacher or doctor, in which case call them -sensei. (And please don’t refer to yourself as -chan or -kun or -san or anything like that, please.)
Also, I’m really against including general address suffixes in translations. They’re in most cases totally unnecessary.
Translation: “Brosh: Edward.”
(Edowaado: Are? Burosshu-gunsou?)
あれ (are): is an interjection being equivalent to “huh?” It come from the pronoun “are,” which means “that thing,” that /a/ being one of those stems we talked about before. (We’ve seen “kore” and “sore,” this is the the /a/ version of that word.
ブロッシュ (Burosshu): is Brosh.
軍曹 (gunsou): is a noun meaning “sergeant.” In the military, ranks are used as address suffixes. That is what is happening here.
Translation: “Huh? Sergeant Brosh?”
よかった (yokatta): is an interjection equivalent to English’s “yes!” It comes from the past, affirmative conjugation of the adjectival verb “yoi,” meaning “good.” (The adjectival verb “ii” comes from “yoi;” and they both mean the same thing.”
Translation: “Brosh: Yes!”
(Edowaado: Oi, dou shita-n da yo.)
おい (oi): is an interjection equivalent to English’s “Hey.”
どう (dou): is an interrogative adverb meaning “how?” or “in what way?”
した (shita): is the indicative, past, affirmative conjugation of the verb “suru,” which we’ve seen plenty of.
ん (n): is another substantivizing suffix. “dou shita-n” is actually a common saying, meaning “What’s the matter?”
だ (da): is the copula.
よ (yo): is the emphatic ending suffix.
We won’t translate this as “it is the case that what’s the matter” because it’s just a common saying.
Translation: “Edward: Hey, what’s the matter?”
(Brosshu: Sugu-ni hoteru e modotta hou ga ii.)
すぐに (sugu-ni): is the verb “sugu,” meaning “immediately” with the adverbial suffix “ni.”
ホテル (hoteru): is a loanword noun meaning “hotel.”
へ (e): is the locative particle.
戻った (modotta): is the indicative, past, affirmative conjugation of the verb “modoru,” meaning “to return.” (If you’re wondering what the difference between “modoru” and “kaeru” is, “kaeru” tends to mean a return to one’s place of origin, like one’s home. “Modoru” can just be to go back to somewhere you were before, but you’re not from here, like a hotel or your temporary living quarters.)
方 (hou): is a dependent noun meaning “direction” or “way.” It is used for this expression: “X hou ga ii” meaning, a bit literally, “the way of X is good,” as in “you should X.”
が (ga): is the nominative particle.
いい (ii): is the indicative, imperfective, affirmative conjugation of the adjectival verb meaning “good,” which we just talked about, in fact.
Translation: “Brosh: You should return to the hotel immediately.”
(Burosshu: Kibou to areba goei mo tsukeru.)
希望 (kibou): is a noun meaning “wish” or “hope.”
と (to): is the quotative particle. We are in the middle of an expression.
あれば (areba): is the -eba conditional conjugation of the copula “aru.” “X to aru” means “a certain X;” and “X to areba” means “if there is a certain X.” “Kibou to areba” is an expression meaning “if you’d like,” as in “if there is a certain wish.”
護衛 (goei): is a noun meaning “guard” or “escort”
も (mo): is the secondary particle meaning “too,” and here “wo” has dropped out.
付ける (tsukeru): is the indicative, imperfective, affirmative conjugation of the verb meaning “to affix [something]” or “to attach [something].” In this case, he is talking about attaching an escort to Edward and Alphonse. If you want to say “to put [them] under escort,” that is fine.
Translation: “Brosh: If you so wish, I will attach an escort.”
(Note: Given the sentence itself, we don’t have any reason to believe that Brosh is talking about serving as an escort himself; and in greater context he is too weak to handle the looming threat.)