Gah, wrapping the math around for adding it all up makes my head hurt.
Let's see...the final is "druid" 5 + 4 Beastmaster +1 Ranger +10 Halfling Outrider for a 30th druid (or 40th if Halfling Outrider double-progresses it from Prestige Ranger)
Ranger 1 + 10 Halfling Outrider for an 11th ranger
Paladin 2 + 10 Halfling Outrider for a 12th paladin
Does that look right?
Good catches on the others, though I knew about the Elf domain being a big stretch
Perhaps still usable in a campaign world where the racial deities for friendly races are combined (Like how Dragonlance has Reorx for kender, dwarves, and gnomes), or a character with a wildly implausible backstory. Or re-flavor the domain so that it applies to forest-living halflings.
Anyhow, my conclusion is that you need flaws to make it a decently playable character unless you start at a very high level. Too bad
Strongheart Halfling Savage Fey Bard 1/Cloistered Cleric 1/Savage Fey Bard 2-5/Prestige Ranger 1/Prestige Paladin of Freedom 2/Beastmaster 1/Halfling Outrider 10
1st flaw: Point Blank Shot
1st flaw: Precise Shot
1st Halfling: Track
1st char: Mounted Combat
3rd char: Rapid Shot
6th char: Endurance
8th bonus paladin: Mounted Archery (Spell-less paladin variant from CC)
9th char: Skill Focus (Handle Animal)
12th char: Devoted Tracker
15th char: Improved Precise Shot
18th char: Hey, an open feat slot! Maybe that Theurgistic Companion thing from Dragon Magazine JaronK mentioned.