OMG, that's rough! The trick to beating it on hard with no lives lost: Learn to use the pineapple! LOL, I use map 2 with 2 boomerang monkeys at the first gently curving portion, and tons of well placed Tack Shooters. I add 2 catapults at the long straight-away and a super monkey, as well as a few other things scattered here and there.
...then...use...pineapples... lots of them, lol. I use them at the starting point to weaken the bloons when they first show up, then put them a short distance ahead of anything dangerous like MOABs and ceramic bloons. Anything yellow and up, bomb it! LOL, it's still really hard though, so don't expect this comment to simply walk you through hard mode
As for the ghost goblin, do NOT use cannons, lol. He can't jump, but cannons will toss him over your army to attack your base unhindered. Stick with casters that have push-back (witches, succubi, and mermaids) and if you must, use archers too, but other than that, trial 5 has very weak troops that die fast and are no threat.
Meh, I prefer the minotaurs to the dragon riders in my army. Bonus against the base, high population, and all-around average to above average troop. When you do the math on their damage, you get more for your money with minotaurs, and can throw in more/better spells while you're at it. My army is usually just Mermaids, Succubi, Witches, Minotaurs, Yetis, and Black Knights. With all the pushback, I had no trouble with the trials, even Trial 5 (actually 5 was the easiest and took less time, lol).
 "Bloons Tower Defense 3"){kind=icon}
 "Epic War 3"){kind=icon}