Thanks for your questions. I have written a number of posts on the place/importance of friendship for the hermit. If you check out the labels to the right you will find at least 10 posts on "friendships and hermiting". You will also find posts on selfishness or self-centeredness and the eremitical vocation. Below I am including one of the posts written within the last three years or so. I think it will answer a lot of your questions even though the questioner had different concerns than you do. Please feel free to get back to me if it fails to satisfy your needs in this; I am happy to say more if I can.
Meanwhile, I think your first questions may refer to concerns Pachomius (4C.) had while living as a hermit. However, others have also raised these questions: how can one learn to love if one is strictly alone, how can one grow in patience or humility without the company of others? Pachomius eventually founded a monastery because he believed living with others was crucial to coming to Christian maturity. In my own life (and in canon 603) I believe the church tries to protect the gift of eremitical life while balancing the fundamental need for community and friendship. Maintaining such balance is demanding and difficult for hermit and friends alike -- but God provides what is necessary here. Certainly the folks who are a hermit's friends are very special and especially graced persons; the hermit gives thanks every day for such friends, relatively rare though they may be!

Thanks for the questions. Let me start with the way friendships are viewed today in religious and eremitical life generally and then tackle the nature of detachment and the kinds of attachments we are called to eschew. Then maybe I can say something about the paradoxical nature of giving one's life to God alone and how it is friendships are ordinarily an indispensable part of that. Finally, I can say something about how it is hermit life changes this somewhat, what it retains, and what might be necessary in the recluse. What you should be doing is a separate question which I think (and hope!) will build on these things.
Friendships are Indispensable Gifts of God:
First it must be said that friendships are a gift from God to each of us and one of the primary ways God's own life and love (for these are identical) is mediated to us. Friendships are also one of those places we can learn to truly love as the great commandment requires. We tend to appreciate this a bit better than has sometimes been true in the history of spirituality. Religious today have friends and good friends. So long as this does not detract from the person's love for her Sisters and commitment to her community which will have priority, such friendships add to her own life and can add to that of her community as well. Especially I think, we see better today than sometimes that to genuinely love another does not prevent us from loving God with our whole hearts, mind, and strength any more than loving God in this way prevents us from loving ourselves or others. Love, which is a transcendent reality and of God, is not divvied up or divided into discrete units so easily as this.

Real Personal Love Involves Detachment:
I think the real problem comes when we are not really loving others (or letting them truly love us) but instead are relating to them for some lesser reason. To be "attached" to someone because we truly love them (and have been able to allow them to love us) really implies significant detachment. We are delighted to be with them; they console and challenge and inspire us, but at the same time we "hold them lightly" and may need to let go of them in the name of love. We cannot cling to them precisely BECAUSE we love them. This paradox I suspect was not always understood enough --- thinking in terms of paradox is not always easy for us, and often feels very unnatural. We tend to think in terms of either/or --- either attachment or detachment, but love introduces us to relationships that are variously intimate, fiercely loyal and committed ("attached") while at their heart being open to what is best for the other to the point of sacrificing our own needs and desires (detachment) in small ways and large for their sake.
The Witness of the Eremitical Life:
The hermit's life is meant to witness to this fact --- not in an elitist way as though it is only true for her or for the rare vocation to eremitism but in a way which affirms this is truth for all of us. She does it in silence and solitude because, in fact, this strips away many of the things we might use to "complete" us falsely, to obscure our vision, or which we mistake either for God or for our truest selves. She does it in the silence of solitude (and with the silence of solitude as the goal and gift of her life) to reveal the truth of who God is and who we all are most fundamentally --- namely, persons who are always and everywhere in intimate dialogue with God. This is the primary reason, I think, why canon 603 does not define the vocation in terms of individual salvation but in terms of being something lived for the redemption of all. I think Thomas Merton saw this clearly when he spoke of the one first duty of the hermit. You may remember that he said,
[[The . . .hermit has as his first duty, to live happily without affectation in his solitude. He owes this not only to himself but to his community [by extension diocesan hermits would say Diocese, and parish] that has gone so far as to give him a chance to live it out. . . . this is the chief obligation of the . . .hermit because, as I said above, it can restore to others their faith in certain latent possibilities of nature and of grace.]] (Contemplation in a World of Action, p. 242) While I agree completely with Merton I would say that to live happily and without affectation in one's hermitage witnesses to the fact that the human being is made for and incomplete without God and therefore is defined by her potential and capacity for Love.
Maturing in Eremitical Life:
It should be clear from all that I have said that growth in the spiritual life does not necessarily mean letting go of authentic friendships. It is far more likely to demand their cultivation --- something we should be aware of in this time and culture of superficial and utilitarian "friending!" Sometimes the literature of exclusion and separation was simply selfish (and not particularly Christian); it failed to see that love of God and love of others are inextricably intertwined and in some ways it prevented even the genuine friendships that are so necessary for growth. That is as true for the hermit as it is for everyone else. In fact it should be noted that the capacity for authentic friendships and relationships generally is presupposed in eremitical life; this is one reason it is considered a second half of life vocation or is perceived as being possible only after years of formation in monastic life. For the hermit the relationship with God is always given absolute priority, and this must occur in the silence of solitude -- which limits and conditions the friendships which are possible. Still, so long as the hermit is faithful in observing these priorities she may very well find her vocation calls for a few really special friendships as well. The hermit may not see these friends often but their love supports and challenges her in ways a solitary vocation really requires.