I know the tower is finished now, but I thought I would give a little advice, at least what I have to offer as someone who has only been playing for a couple of no ths…well almost. Anyway, I am currently rank 33, and have a few ideas for you.
It seems you have been fortunate enough to a quote some pretty good hatched. The monsters you have are alpt stronger ultra evolved. When I was your rank, is around the time I began to ultra evolve, and put all my efforts to it. Well, mostly… And and put all else on hold. All of your gold and silver keys are essential in unlocking true strength and potential of your monster family. 
… If you collect enough silver and youth fruit, and strategically take the right steps when training, you can quickly evolve them. That Megarex is one who will have pretty great strength, and he is easy to ultra evolve. Don’t be afraid to spend a gem or two to refill your tickets for acquiring needed fruit, silver, and ingredients. Anyway that’s enough about that, but it IS important…
Also, try and find monsters who have dual poison touch, and poison massacre. Put a monster in line right before him, that when it is knocked out, has poison revenge. That way, when the next monster comes out, who has poison massacre, he will most likely be able to knock all 4 who are facing you currently… same goes with dreamhunt, with a monster who can sacrifice itself to put all of the enemies to sleep. It doesn’t take out all of them like poison massacre, but you can focus on a strong target…
Lastly, the only other thing I can currently think of, is to put one or two strong monsters in your first four starters, and one or two throughout, but make sure a couple are at the end, ready to strongly stand up to the last monsters your have to face. Preferably one with last stand who may be the last one you jave, and can try amd pick off the last couple with the last stand move…
Other than all that, strategy comes to each person differently as they play the game. Try and think of your own ways of winning that others may not pick up on. Your assessment of your monsters strengths and weaknesses is everything. That’s why I love this game, there is alpt to figure out about winning, as you go along. These things should help you for now, to begin to get stronger and stronger. Hope to meet you on the verses field one day 
Mostly agree,but I rather Advice you to put snowja in front and support him with stun sacrifice.after that,you can use poision team.I have him and after ultra,he will get one by one skill,very useful since you have 400 bomb monster.
Have fun
Arash