Well, the first thing you do is think of the "contour" of the wave a ricochet makes. So for a ricochet its more of a Pionnnnnnnn or pewwwww.... have a fast attack and a nice sustain kind of like so ">".

for this one there is many ways i have seen people do it to throwing certain coins on certain material or hitting a wooden hammer on some springs to get that sustain. I have even seen people record a motocycle or maybe a moped with a more "midsy" sounding engine and just reocrd a sample of it passing by them and speed it up to remove the audible sound of a passing engine. You can try different things, mostly you would want a fast attack, something very percussive and have it ring. if it doesnt sound metallic enough for you, sometimes a phaser or even alittle bit of spring reverb cant make it sound metallic.

 Its hard to explain foley on certain sounds, cause there is usually more reasons then I will ever know.  

I am a pc guy. Majority of D.A.Ws that are for mac/pc can usually do everything you need. I feel each D.A.W has the capability to do each thing correctly depending on your work flow, but they seem to be built with a certain thing in mine. Like  Pro Tools seems to be made for actually recording live/studio sessions. Where it lacks in the midi department I wouldnt think its ideal for games, although it is still good for both. one I use ableton, which is great for automation,midi, warping, sampling and DJ type work. Which is good for me to get what I want. Majority of everything i have posted on this website was done in ableton. 

When it comes to open source alternatives, there isnt really much. There is audacity, Although it can be done, and i have done it quite a few times out of boredom. It doesnt exactly have all the parameters for someone like me to use. Thew few two I can think of that are worth trying of the top of my head is LMMs and RoseGarden. I havent used LMMS very often but when I use to carry my laptop around with linux on it I would dable in Rosegarden (which to me for a free software) was very well rounded in terms of midi, and audio. So you might want to try that out.

 for me, its just hard to use programs like that cause I have gotten to the point where I need to have certain plugins, or certain D.A.Ws for certain things. Even some plugins within some D.A.Ws i cannot stand. The reverb in ableton is one I cannot stand. The coding for that plugin makes a sound sound too bright (even with the Diffusion parameter cranked up). When as you know, Reverb is what you use in a stereo setting to make things sound up close or far off in the distance and if you use reverb to make something sound far off in the distance High frequencies begin to dissipate making the waveform darker.