You are attacking across a rather significant 'river' (thus the minus 60 modifier).
As to the amorphous issue - there is something going on here. It looks like the created creature has this characteristic WITHOUT it being listed in the unit description. This wouldn't shock me at all (given how things have developed) and you only found it by doing the detailed report (many things are 'present' in the game WITHOUT being specifically listed). This is slowly being corrected - but don't be shocked to find more instances of this throughout the game. The game DOES NOT have any sort of built in 'balancing mechanism' to make sure you have a 'fair chance' against whatever starting conditions are present. So the longer alien life has to evolve on a planet - the tougher that life will be. YOU must compensate by starting with a higher initial tech level and multiple zone start-up. The only way you gain a 'feel' for this is through playing on multiple games and developing a level of intuition for what is happening and how to adapt to it.
About the only REAL solution to this, is to start off with a higher tech level - thus giving you the firepower and recon to deal with alien life early on in the game. This is one of the issues that has slowly crept into the game since its original beta testing 2 years ago - the 'fauna' has become more and more sophisticated it seems (it seems).
I find it nearly impossible to start a game on tech level 3 with no starting army, single zone and slowed tech development any more (with any form of alien life wandering around). I just get swamped in the first 10-15 rounds in these situations. That second critter - if it indeed possesses the amorphous characteristic - would be virtually impossible to battle with low quality infantry alone. You would have to use armor or aircraft to gradually wear it down. The higher tech weaponry with the higher recon levels available would be able to deal with this critter rather easily. Using artillery and airpower to wear down this creature and lower readiness would be another way to deal with it.
It looks like you had a VERY long time period of evolution occur on the planet you created (I'd say at least 2 billion years given the sophistication of those critters), so you are going to be faced with a VERY difficult time dealing with them with anything less than tech level 4 and multiple zone start up.
- Entangler Rhino.jpg (64.71 KiB) Viewed 828 times
Here is a critter from a game I just ended (playtesting Oceania so I started a new game under latest version) that just gave me FITS. It would be present in VERY large herds and had the amorphous V characteristic. The only way I could deal with it (using pure infantry) was to surround it with 3 entire brigades of troops equipped with auto rifles and combat armor - and do so in clear terrain. This thing pretty much wandered where ever it wanted to and there wasn't a thing I could do about it. The only saving grace about it was that it wasn't aggressive. This was on a planet that only had a billion years of evolution (I started at level 3 tech, 1 army, extremely slow tech development). It wasn't until about round 50 that I could start to effectively deal with it.
Hope this gives you some insight.
. I had tough times at beginning. Started with T3, slow research and one zone. Very quickly, major regime on eastern border declared war and invaded my territory. I was surprised to find they have combat armor and automatic rifles while I was still researching padded envirosuits. Somehow I managed to stop them by digging units into forest belt (+150 entrenchment bonus), by putting my HQ's on defense (+40 defense bonus) and by playing "Docile AI" cards to bolster defence with walkers. 
However, this game is fascinating and I'm still learning. And your explanation helped me to deepen the knowledge.