What an interesting and difficult question!
/i/ and /I/ Final location: Tea and Tee
This pair does not correctly distinguish the 2 different sounds because tea and tee have exactly the same pronunciation.
/r/ and /l/ Final location: boar and ball
Ball for the final /l/ is correct. It’s difficult to find a word in the English language where the final “r” is pronounced. I’ve been thinking about this for a while and have not come up with anything; the final “r” is usually silent. In your example of boar, the final sound is the vowel. I wonder if with a Scottish accent, the final “r” is sometimes pronounced. Do we have any Scottish members out there who could enlighten us?
I’m afraid, I haven’t come up with a minimal pair to illustrate the final /r/ and /h/ because of the explanation above. Final “r” and “h” are usually not pronounced; or the “h” is pronounced along with other letters, e.g. “tch”. As these sounds are not normally pronounced at the end of a word, I wonder why you are teaching it. Pure curiosity, there’s maybe something I haven’t thought of!