these are typically requested to go in team-help, but I'll go ahead and respond.
your team is very early game, as I'm sure you well know; you're not so much 'going rainbow' as simply lacking bench depth. you field what you've got, and will continue going with the best of what you've got for some time now, until you start to see a pattern emerge or define one yourself.
That's not to say you have to sit back and let it happen.. your scout choices, above just about everything (especially with element-specific draws leaving), will shape where your team is headed. Soccer spirits, on the long-haul meta game, is about resource management as much as it is about building a team or figuring out who goes where. With that in mind, you should not be scouting any players that you do not want to eventually see in your final deck(s). Frankly, any card with a 7star option is going to be a 'good fit for [your] team' simply because you need just about everything. That's short-term though.
The question you need to answer for yourself, is what is the team you eventually want to move toward. Your lucid and bora are both good (lucid is #1 supremo PVE striker.. it does not get better.. but she's lack-luster in pvp), but beyond those most of the cards you have are pretty filler-role type cards. You could say you have (sortof) the early makings of a red/green team, but that's without any of either red or green that you really, really want. Envision your ideal team... guess what you think may be released in the future (is there going to be a blue/purple ace? dunno, but there may be) and build toward that.
So what are you getting with Hildegard at end-game: at 7star, 5/5+120 hildegard is a laser-guided missile nearly guaranteed to 1-shot anything that sits in front of her, unless it's the GK itself (though sometimes that too), or she gets counter-attacked by reflex. Her role is to blow a hole in whichever line she's placed (and very likely those in front of that). She has the added benefit of dropping the action bar of the entire enemy row that she is placed in (not the rows she hits later on, but her original placement). She is must-have if you need a penetrator for blue or one of blue's hybrids. She's ideal for a mid-line wing or a defensive line center. My hildegard is in the back row and her typical action looks like this: smack back mid for 1800-2300, hit both mid for 7-800 (assuming its 4man mid), hit GK. That's with good stones, a unique, and good line buffs (yuri+mikael+kevin).
While she does her one mission beautifully, she will not survive many hits receiving unless you have ample life-steal on her, she provides no buffs to her line, and is ideally suited to teams that can hybrid around thunder. Thunder is in a bad way of late, so unless you want to build a team around silla (really the only top-tier 'rainbow' ace; malcolm is a maybe) you're either hoping to get a hiro, building something around a pure thunder ace (jury/blade/etc) or hoping future thunder hybrid options are better.
Short-term hilde would be a great addition and if you feel like you'll build the GP back up by the time you can scout another, I'd so go ahead and pick her up.. but if you're wary long-term and think you may not want to build around thunder, I'd get yourself a top-tier goalie (jin/kei/lucian/zibroi), or look for hyrbid ace options and start building into that (lucian,sammy, saramir, or niarose would build reasonably out of what you've got).
tl;dr.. maybe?